SFP Alpes

Doru C. LUPASCU (Institute for Materials Science and CENIDE - Faculty of Engineering, University of Duisburg-Essen)
2026-02-06 10:30 - 12:30 (Europe/Paris) | ILL – Salle de Séminaire (110-111), ILL 50 71 avenue des Martyrs, Grenoble, 38042, France
Hyperfine Interactions as a Probe in Solids : The Example of a Multiferroic System : Bismuth Ferrite
Hyperfine interactions denote the coupling of the wave functions of nuclear states to the electronic shell of the atom. This coupling is a correction term to the energy of a nuclear state and equally so in reverse manner for the electronic shell of the atom.
Like nuclear magnetic resonance or Mössbaer spectroscopy, the nuclear perturbed gamma-gamma-angular correlation spectroscopy (PAC) investigates this energetic modification of the nuclear state. For sufficiently high nuclear spin value, magnetic interactions as well as quadrupole interactions become accessible. The beauty of the method is its highly local character in the crystal lattice. It directly monitors fields at a particular lattice or defect site. Similar is true for molecules.
Bismuth ferrite is a perovskite crystal exhibiting magnetic and electric ordering phenomena. It is antiferromagnetic and a very good ferroelectric. We used several probe atoms that offer suitable nuclear gamma-gamma cascades to understand these two ordering phenomena in the identical crystal and their coupling. Different from the long term belief, we proved that there is no magnetoelectric coupling in this crystal.
The presentation will introduce the measurement method, and the material system and display how it can be used to investigate solids in a very local manner.
—
Hanno Filter (College 3 Secretary)
External visitors may ask for a site access to tellier(at)ill.fr
Zoom link : https://ill.zoom.us/j/98964195699?pwd=[REDACTED] – Password : [REDACTED]

William FAUGNO (LKB / Collège de France)
2026-02-06 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Quantum Many-Body Scars in the Presence of Density-Difference-Dependent Hopping
Résumé :
It has been observed that isolated quantum systems often still produce measured values consistent with thermalization. This is unexpected due to the lack of a notion of chaos or ergodicity and the unitary dynamics of the quantum theory which is at its core linear. The conditions under which we can expect isolated quantum systems to thermalize were laid out in the eigenstate thermalization hypothesis (ETH), which has generally been found to hold in a variety of systems. Still, notable violations of the ETH have been identified where a seemingly chaotic many-body quantum system exhibits some nonthermal behavior. In this talk, I will introduce the concept of quantum many-body scars (QMBS), a phenomenon in which a small subset of eigenstates violates the ETH and promote nonthermal dynamics. I will then present theoretical results on a bosonic Hamiltonian with a density-dependent hopping and describe two distinct mechanisms for scar formation that arise in this model. These mechanisms provide insight into the conditions under which QMBS can be expected to occur.
Contact : serge.florens@neel.cnrs.fr

Kei YAMAMOTO (Advanced Science Research Center, Japan)
2026-02-06 11:00 - 12:00 | CEA – Salle de Séminaire IRIG (1005 – 445), Laboratoire Irig/Spintec, salle de séminaire 445, bâtiment 1005, CEA-Grenoble, Grenoble
Spin-wave spectrum in a ferromagnetic disk
Abstract :
Angular momentum transfer in all forms contributes to the loss of information carried by dynamical spin polarisations and constitutes an important fundamental problem in spintronics. In this talk, we present a detailed microwave spectrum measurement of magnetic excitations in an Yttrium Iron Garnet disk, and how one can make sense of the multitudes of spectral lines and their magnetic field dependence theoretically. We explain how the axial symmetry of the setup leads to labelling of modes in terms of the conserved total angular momentum of the spin waves, The frequency spectrum in the saturated state is compared to analytical solutions for pure exchange as well as pure dipolar models under certain limits where different types of spectral degeneracy occur. The experimental result shows splittings of those degenerate modes, and we discuss possible interpretations in relation to angular momentum transfer between its different forms.
​​
More information :https://www.spintec.fr/seminar-spin-wave-spectrum-in-a-ferromagnetic-disk/​​​
​
Visioconference :https://univ-grenoble-alpes-fr.zoom.us/j/98769867024?pwd=[REDACTED]​​

Isidora ARAYA DAY (DIPC San Sebastian)
2026-02-09 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Diagnosing higher order topological phases with electronic transport
Résumé :
Unlike a quantum Hall bar, a higher-order topological insulator may not have edge modes that conduct, but localized corner modes. These corner modes are robust to disorder and their appearance is diagnosed by a topological invariant that takes both onsite and spatial symmetries. In this talk, I will introduce a scattering theory for detecting higher-order topological phases only from a sample’s Fermi level properties, and will demonstrate how to apply it to different models. This theory provides an alternative approach for proving bulk–edge correspondence in intrinsic higher order topological phases, especially in presence of disorder, and it relies on the spectral flow that these phases show in the presence of magnetic flux.
Contact : serge.florens@neel.cnrs.fr

Stéphanie ROCCIA (LPSC-CNRS/UGA, Grenoble)
2026-02-10 10:30 - 11:30 | ILL – Salle de Séminaire (110-111), ILL 50 71 avenue des Martyrs, Grenoble, 38042, France
The search for neutron electric dipole moment at PSI
Résumé :
The Universe and its history are simultaneously very well understood and still a big mystery. We have amazing tools from satellites to
observatories to weight the universe over its history. But the components of the Universe can simply not yet be explained by physicists. To get the full picture, we need to identify and understand the interactions at play throughout the life of the Universe. This is the meeting point between particle physics and cosmology. At this meeting point stands the neutron, a common particle that we can uniquely use in high precision experiments.
I will present how experiments searching for a permanent electric dipole moment of the neutron (nEDM) aim at discovering new sources of CP violation beyond the Standard Model of particle physics and understanding the origin of the matter-antimatter asymmetry of the Universe. The quest for the neutron electric dipole moment started more than sixty years ago. In recent experiments, polarized ultra-cold neutrons are stored in material bottles.
I will present the ongoing efforts at the Paul Scherrer Institute in Switzerland where the n2EDM spectrometer has taken the first “physics data” in 2025. A large fraction of this dataset is dedicated to measurements of the UCN spectrum. I will present the newest UCN spectroscopy techniques that were recently published and the reasons for the importance of a deep understanding of the UCN spectrum.
—
Hanno Filter (College 3 Secretary)
External visitors may ask for a site access to tellier(at)ill.fr
Zoom link : https://ill.zoom.us/j/98964195699?pwd=[REDACTED] – Password : [REDACTED]

Roxane LESTINI & Nicolas OLIVIER (Laboratoire d'Optique et Biosciences, Palaiseau)
2026-02-16 11:00 - 12:00 | LiPhy, Salle de Conférence, 140 rue de la Physique, St Martin d'Hères, 38400
Understanding DNA replication dynamics in the archaea Haloferax volcanii
Résumé :
Archaea provide a simplified yet highly informative model for deciphering the complex regulatory networks governing DNA replication and origin firing. Among them, Haloferax volcanii has a circular chromosome with four active replication origins distributed across a 3.5 Mb DNA molecule and exhibit some distinctive properties, such as a heterogeneous polyploidy, carrying 10–18 copies of its genome.
How these highly polyploid organisms regulate the activation and timing of their multiple replication origins in coordination with cell growth and division remains an open question. To address this question, we developed a multiscale approach, implementing the STORM technique in archaea for the first time, Marker Frequency Analysis by sequencing (MFA-seq) to capture the global replication profile at the population level, and fluorescence in situ hybridization (FISH) to explore ploidy variation.
Our findings reveal, with an unprecedented resolution of ~30 nm, new insights into the spatial regulation of replication foci, demonstrating their organization into clusters. We further investigated DNA replication dynamics under varying growth conditions, revealing a reduction in replication foci number that correlates with decreased replication rates and DNA content. By contrast, altering the replication initiation mode—by inactivating all four replication origins—does not disrupt the overall replication dynamics.
By integrating these techniques, we aim to characterize the replication program in H. volcanii and gain a deeper understanding of its regulation.
Contact : delphine.debarre@univ-grenoble-alpes.fr

Francesco ROSA (Politecnico di Milano, Italy)
2026-02-17 14:00 - 15:00 | CNRS – Salle Louis Weil (E424), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Magnetic and orbital properties of infinite-layer nickelate and cuprate superconductors
Résumé :
Infinite-layer (IL) nickelates recently gained strong interest thanks to their apparent analogies with cuprates, including a square lattice-based structure dominated by superexchange antiferromagnetic interaction and the emergence of superconductivity upon hole doping. X-ray spectroscopies with synchrotron light are a very powerful tool for the investigation of such systems, providing complementary information to the more traditional inelastic neutron scattering. In this seminar, we discuss some of the recent results obtained by our group using both Resonant Inelastic X-ray Scattering (RIXS) and X-ray Magnetic Circular Dichroism (XMCD), mainly focusing on magnetism. RIXS results concern the analysis of dynamic spin excitations (magnons/paramagnons), investigating the effect of hole-doping on them and providing an estimate for the magnetic exchange coupling constants. Results on IL nickelates will be compared to analogous ones on cuprates, highlighting analogies and differences. XMCD analysis is devoted to the static spin order in IL nickelates, reporting the presence of a field induced out-of-plane Ni1+ spin moment. Based on magnetic field- and temperature-dependent measurements, we justify our observations with an out-of-plane canting of in-plane anti-ferromagnetically correlated Ni1+ spins, tentatively attributed to a symmetry lowering of the NiO2 planes.
_
Contact : andrew.fefferman@neel.cnrs.fr

Anton POTOCNIK (IMEC, Belgium)
2026-02-17 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
High-coherence foundry-compatible superconducting qubit platform
Résumé :
The field of superconducting qubit technology has experienced rapid development over the past two decades. Recent advancements in the fabrication, control and measurement of superconducting quantum devices have enabled integration of hundreds of qubits on a single chip. However, the path towards larger-scale integration of thousands of qubits on a chip remains unclear. This talk presents imec’s platform for scalable superconducting qubit fabrication, which is based on foundry-compatible thin film processing 1 and overlay Josephson-junction fabrication 2. The platform enables all-optical superconducting transmon qubit fabrication on 300 mm wafers, achieving near state-of-the-art coherence times, record-low aging and comparable Josephson junction variability to standard shadow-evaporation technique 3. A key focus of this presentation will be the understanding and mitigation of microwave losses induced by various fabricaiton steps such as Ar-milling 4 and oxide removal 6,7 and materials such as -Ta 5 or ultra-high-resistivity silicon. The talk will conclude with an outline of ongoing efforts toward large-scale qubit characterization and control using cryo-CMOS electronics operating near qubits at the mixing-chamber plate of a dilution refrigerator 8.
1 Mongillo, et al., IEDM (2022).
2 Verjauw et al., npj Quantum Information 8, 93 (2022).
3 Van Damme, et al., Nature, 634, 74 (2024).
4 Van Damme, et al., PRA 20, 014034 (2023).
5 Lozano, et al. Mater. Quantum. Technol. 4, 025801 (2024).
6 Verjauw, et al., PRA 16, 014018 (2021).
7 Lozano, et al., Advanced Science 12, e09244 (2025).
8 Acharya, et al., Nature Electronics, 6, 900 (2023).
_
Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr

Igor ROZHANSKIY (National Graphene Institute, University of Manchester)
2026-02-17 14:00 - 15:00 | CEA – Salle de Séminaire IRIG (1005 – 445), Laboratoire Irig/Spintec, salle de séminaire 445, bâtiment 1005, CEA-Grenoble, Grenoble
Interacting spin physics in 2D : flat bands, SOC renormalization, and chiral textures
Résumé :
Two-dimensional materials and their heterostructures offer a controllable setting where exchange, spin-orbit coupling (SOC), and electron interactions shape the spin-resolved electronic structure and response. This seminar links two recent directions of my work through this common theme.
The first part focuses on van der Waals magnets (chromium trihalides) combined with graphene. Narrow, spin-polarized conduction bands make these systems susceptible to charge-transfer-driven doping and strong correlations. Using DFT-calibrated effective tight-binding models, I will show how flat-band features and longer-range hopping processes determine the low-energy spectrum and favor regimes with heavy, strongly interacting carriers.
​ The second part addresses many-body renormalization of SOC in monolayer transition metal dichalcogenides. Exchange effects can enhance the conduction-band spin-orbit splitting in a density-dependent manner. I will outline ​the underlying mechanism and discuss how it can be inferred from gated transport and quantum-oscillation measurements, including multilayer configurations where valley structure and interlayer coupling provide additional diagnostics.
A short outlook will touch on chiral spin textures, such as skyrmions, and how real-space chirality can contribute to transverse signals, emphasizing possible connections and open questions for 2D material platforms.
https://www.cea.fr/drf/irig/Pages/Animation-scientifique/seminaires/2026_Rozhanskiy.aspx
Contact : admin.spintec@cea.fr

Dmitri KHVESHCHENKO (University of North Carolina)
2026-02-20 11:00 - 12:00 | LPMMC, CNRS - Bat G, salle Roger Maynard G-421, Grenoble
Applied Hall-o-graphy with no strings attached
Résumé :
This discussion aims at ascertaining the true status of the so-called applied-holographic approach to strongly correlated quantum matter. The latter ranges from ‘not even wrong’ for the constructions based on the ad hoc ‘AdS/CMT’ to ‘might be right, albeit for the wrong reason’ for those emerging in the context of phase-space bosonization and the related ‘Hall-o-graphic’ hydrodynamics.The presentation will be made accessible to the wide audience of non-experts and students.
Contact : serge.florens@neel.cnrs.fr

Rolf LORTZ (CNRS-LNCMI, Grenoble)
2026-02-26 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
High temperatures superconductivity with giant pressure effect in 3D networks of boron doped ultra-thin carbon nanotubes in the pores of ZSM-5 zeolite
Résumé :
We report the fabrication of three‑dimensional, interconnected networks of ultrathin carbon nanotubes (CNTs) embedded within the ~5 Å pores of zeolite ZSM‑5 crystals using a controlled chemical vapour deposition (CVD) process. Confinement within these sub‑nanometre channels yields CNTs with strongly one‑dimensional electronic characteristics, including pronounced van Hove singularities in the density of states. By introducing boron dopants during growth, we strategically tune the Fermi level toward a van Hove singularity, as supported by ab initio electronic‑structure calculations. This electronic tuning, combined with the intrinsic 3D connectivity of the CNT–zeolite framework, enables a dimensional crossover from 1D electronic states to a phase‑coherent, bulk superconducting state.
To establish the presence of superconductivity, we employ five complementary experimental probes—electrical resistivity, ac susceptibility, dc magnetization, specific heat, and point‑contact spectroscopy. All measurements consistently indicate a superconducting transition at ambient pressure with a critical temperature Tc in the range of 220–250 K. Simultaneous resistivity and ac‑susceptibility measurements reveal a three‑order‑of‑magnitude drop in resistance accompanied by the onset of a robust Meissner effect with nearly perfect diamagnetic screening. Point‑contact spectroscopy further uncovers a multigap superconducting state, with a dominant gap of approximately 30 meV, in reasonable agreement with expectations from Bardeen–Cooper–Schrieffer (BCS) theory. The differential conductance spectra exhibit clear particle–hole symmetry and evolve smoothly between the tunnelling and Andreev reflection regimes as the contact transparency is varied—behaviour uniquely characteristic of superconducting quasiparticles. Specific‑heat measurements show a distinct anomaly at the transition, reminiscent of signatures observed in high‑Tc cuprate superconductors.
Finally, we find that the application of very modest external pressure further enhances the superconducting transition temperature, pushing Tc above ambient temperature and suggesting that the system remains far from its optimal tuning point. These results collectively point to a new pathway for achieving high‑temperature superconductivity in engineered low‑dimensional carbon‑based materials.
Contact : florence.levy-bertrand@neel.cnrs.fr

Matteo MILANI (ESPCI Paris)
2026-03-02 11:00 - 12:00 | LiPhy, Salle de Conférence, 140 rue de la Physique, St Martin d'Hères, 38400
Rheofluidics: single-drop oscillatory rheology with microfluidics
Résumé :
The measurement of frequency-dependent viscoelastic moduli is of paramount importance in many fields, from material science to biology, and is typically accomplished in bulk materials using commercial rheometers. The trend towards miniaturization in the biotechnology, manufacturing and chemical processing industries has motivated the extension of viscoelastic measurements to microscopic objects with well-defined shape and size such as droplets, vesicles, microcapsules, or even single cells. For instance, local mechanical probes such as AFM nanoindentation can be used to probe single-cell stiffness, and micropipette aspiration probes the interfacial properties of droplets and vesicles. Despite their versatility, these techniques are characterized by complex deformation geometries and a relatively low throughput, which makes them unfit to sample highly heterogeneous populations such as those typical of biological samples. To this end, novel microfluidic approaches have been recently developed to measure the stiffness of cells and droplets flowing through narrow channels. These approaches are well-suited for applications requiring a high throughput, but they lack the fine control of stress and strain required by quantitative mechanical measurements. Here, we present a novel technique called Rheofluidics, which combines the high throughput of microfluidics with the versatility of traditional rheological probes. Like a stress-controlled rheometer, Rheofluidics measures the time-dependent deformation of droplets subject to a well-defined hydrodynamic stress, whose time evolution is controlled by the shape of the microfluidic channel in which the droplets are flowing. To validate this approach and to demonstrate the power of this technique, we study the linear and nonlinear rheology of oil droplets, hydrogel beads and lipid vesicles, extracting their viscoelastic properties with a throughput more than 1000 times higher than that of standard rheology.
Contact : gwennou.coupier@univ-grenoble-alpes.fr

Ran TAO (Institut Néel)
2026-03-02 14:00 - 15:00 | CNRS – Salle Louis Weil (E424), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Magnetic excitations in LuFe2Ge2
Résumé :
The iron-based superconductor YFe2Ge2 (Tc ~ 1.8 K)[1] has attracted interest due to strong electronic correlations[2] and shows enhanced magnetic fluctuations in neutron scattering[3]. Its isoelectronic and isostructural sister compound LuFe2Ge2 orders antiferromagnetically below TN ~ 6.8 K, and in clean crystals shows a resistive superconducting transition below 1 K. We present recent inelastic neutron scattering experiments on LuFe2Ge2 in the ordered and paramagnetic phases. The excitations are modelled with linear spin wave theory, and we note some similarities to previous results in paramagnetic YFe2Ge2.
[1] J. Chen et al., Phys. Rev. Lett. 125, 237002 (2020).
[2] J. Baglo et al. Phys. Rev. Lett. 129, 046402 (2022). B. Xu et al., Proc. Natl. Acad. Sci. U. S. A. 121, e2401430121 (2024).
[3] H. Wo et al., Phys. Rev. Lett. 122, 217003 (2019).
_
Contact : andrew.fefferman@neel.cnrs.fr

Dalila BOUNOUA (LLB)
2026-03-05 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Polarized Neutrons Reveal Altermagnetism in MnF2
Résumé :
Altermagnets constitute a recently identified class of collinear, magnetically compensated materials in which oppositely oriented magnetic sublattices cannot be mapped onto each other another by a primitive lattice translation or inversion operation. Unlike conventional antiferromagnets, altermagnets break time-reversal symmetry. These distinctive symmetry properties give rise to spin-split electronic bands and chirality-split magnon branches, both exhibiting characteristic anisotropic patterns in momentum space, even in the absence of relativistic spin-orbit coupling [1].
Experimental evidence for spin-split electronic bands has been reported in materials such as MnTe and CrSb using angle-resolved photoemission spectroscopy (ARPES) [2,3], while resonant inelastic X-ray scattering (RIXS) has revealed chiral magnon excitations in CrSb [4]. Polarized neutron scattering, however, provides a unique probe of altermagnetism, as it enables a direct characterization of spin-wave excitations and allows both split magnons [5-7] and their associated chirality [8-10] to be measured simultaneously.
In this work, we investigated the chirality-split magnon spectrum of MnF₂ [9] using polarized inelastic neutron scattering (INS). Our measurements reveal, for the first time in MnF₂, a small but clearly resolvable splitting of the magnon branches, primarily driven by long-range dipolar interactions. Polarization analysis on a magnetically domain-biased sample further uncovers a finite chiral contribution to the neutron scattering cross section, which reverses sign between the two split magnon modes. These observations provide direct spectroscopic evidence of altermagnetism in MnF₂.
[1] G. L. Smejkal et al., Phys. Rev. X 12, 040501 (2022).
[2] J. Krempasky, et al., Nature 626, 517–522 (2024).
[3] S. Reimers et al., Nat. Comm 15, 2116 (2024), G. Yang et al. Nat Commun 16, 1442 (2025).
[4] N. Biniskos et al., Nat Commun 16, 9311 (2025).
[5] Z. Liu Phys. Rev. Lett. 133, 156702 (2024).
[6] Q. Sun et al., Phys. Rev. Lett. 135, 18 (2025).
[7] A. K. Singh et al., arXiv:2511.16086.
[8] P. A. McClarty et al., Phys. Rev. B 111, L060405 (2025).
[9] Q. Faure at al., arXiv:2509.07087 (under review).
[10] J. Sears et al., arXiv:2601.04303v1

Contact : elsa.lhotel@neel.cnrs.fr

Kilian FRABOULET (Max Planck Institute Stuttgart)
2026-03-06 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Competing orders in many-electron systems: a renormalization group perspective
Résumé :
The renormalization group is an established approach to study quantum many-body systems, and this applies especially to one of its modern implementations known as the functional renormalization group (fRG). In particular, the fRG constitutes a flexible and unbiased tool for the study of competing orders. In this talk, I will outline recent progress in this direction for correlated electron systems. To this end, I will first discuss the competition between antiferromagnetism, charge density waves and superconductivity in the 2D Hubbard model, thus making a connection with high-temperature superconductors. The special role of bosonization methods will be emphasized along the way. I will also show how the fRG can be combined with dynamical mean-field theory to treat strongly interacting regimes, with a focus on d-wave superconductivity. As a next step, I will increase the complexity of the model by including non-local interactions and discuss unconventional superconductivity in an extended Hubbard model with a connection to moiré materials. Special consideration will also be given to the treatment of retarded interactions with electron-phonon couplings. Finally, I will highlight recent fRG studies of quantum criticality in Dirac materials, with a connection to graphene.
Contact : serge.florens@neel.cnrs.fr

Marek BARTKOWIAK (Paul Scherrer Institut)
2026-03-09 14:00 - 15:00 | CNRS – Salle Louis Weil (E424), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Spin-orbit control of antiferromagnetic domains without a Zeeman coupling
Résumé :
Encoding information in antiferromagnetic (AFM) domains is a promising solution for the ever growing demand in magnetic storage capacity. The absence of a macroscopic magnetization avoids crosstalk between different domain states, enabling ultrahigh density spintronics while being detrimental to the domain detection and manipulation. Disentangling these merits and disadvantages seemed so far unattainable. We report evidence for a new AFM domain selection mechanism based on non Zeeman susceptibility anisotropy induced by the relative orientation of external magnetic fields to the k-domains. Consequently, the charge transport response is controlled by the rotation of the magnetic field and a pronounced anisotropic magnetoresistance is found in the AFM phase of bulk materials Nd$_{1−x}$Ce$_x$xCoIn$_5$. Our results and the domain switching theory indicate that this constitutes a new effect which might be universal across multiband materials. It provides a novel mechanism to control and detect AFM domains, opening new perspectives for AFM sprintronics.
Contact : andrew.fefferman@neel.cnrs.fr

Synergies in High Resolution Spectroscopy workshop (HIRES2026)
2026-03-10 00:00 - 2026-03-13 23:59 | ILL – Salle de Séminaire (SB-036), ILL 71 avenue des Martyrs, Grenoble, 38042, France
The workshop will bring together researchers in the fields of neutron spin-echo, backscattering, and time-of-flight (TOF) spectroscopy. It aims to highlight the strengths and synergies of these techniques, while also showcasing their interplay with other non-neutron-based methods.
Participation is not limited to neutron experts, users of complementary techniques who wish to expand their research toward neutron scattering are also warmly welcome.
Abstract submission deadline is 30 November 2025.
For full details please visit the website of the workshop: https://workshops.ill.fr/e/HIRES2026

If you have any questions don’t hesitate to contact the Organising Committee by e-mailing to hires@ill.fr

Synergies in High Resolution Spectroscopy workshop (HIRES2026)
2026-03-10 08:30 - 2026-03-13 12:00 | ILL 4, Grenoble, 38000, France
The workshop will bring together researchers in the fields of neutron spin-echo, backscattering, and time-of-flight (TOF) spectroscopy. It aims to highlight the strengths and synergies of these techniques, while also showcasing their interplay with other non-neutron-based methods.
Participation is not limited to neutron experts, users of complementary techniques who wish to expand their research toward neutron scattering are also warmly welcome.
For full details please visit the website of the workshop : https://workshops.ill.fr/e/HIRES2026
If you have any questions don’t hesitate to contact the Organising Committee by e-mailing to hires@ill.fr
_
Contact : HIRES2026@ill.fr

François PARMENTIER (Laboratoire de physique de l'école normale supérieure)
2026-03-10 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Quantized heat flow in the Hofstadter butterfly
Résumé :
When subjected to a strong magnetic field, electrons on a two-dimensional lattice acquire a fractal energy spectrum called Hofstadter’s butterfly. In addition to its unique recursive structure, the Hofstadter butterfly is intimately linked to non-trivial topological orders, hosting a cascade of ground states characterized by non-zero topological invariants. These states, called Chern insulators, are usually understood as replicas of the ground states of the quantum Hall effect, with electrical and thermal conductances that should be quantized, reflecting their topological order. The Hofstadter butterfly is now commonly observed in van-der-Waals heterostructures-based moiré superlattices. However, its thermal properties, particularly the quantized heat flow expected in the Chern insulators, have not been investigated, potentially questioning their similarity with standard quantum Hall states. Here we probe the heat transport properties of the Hofstadter butterfly, obtained in a graphene / hexagonal boron nitride moiré superlattice. We observe a quantized heat flow, uniquely set by the topological invariant, for all investigated states of the Hofstadter butterfly: quantum Hall states, Chern insulators, and even symmetry-broken Chern insulators emerging from strong electronic interactions. Our work firmly establishes the universality of the quantization of heat transport and its intimate link with topology. A. Zhang, et al., arXiv:2601.05694 (2026)
Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr

Tymoteusz TULA (LPMMC, CNRS, Grenoble)
2026-03-11 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
One-to-one correspondence between two-point correlators and entanglement in magnetic systems
Résumé :
There are multiple measures of multipartite entanglement — including entanglement in thermal mixtures — currently used to study many-body interacting systems. Recently, Quantum Fisher Information has been proposed as a multipartite entanglement measure that can be connected to experimentally accessible observables. In this talk, I will present our recent findings about a one-to-one correspondence between two-point correlators and a certain general class of Heisenberg-like Hamiltonians and wavefunctions. This is a foundation of our claim that a mapping from finite-temperature observables to any entanglement measure exists for such systems. Furthermore, I will present our results of training a convolutional neural network (CNN) to recognize and predict the entanglement for one-dimensional anisotropic XY and XYZ models, which exhibit an entanglement transition. From our preliminary results we found that entanglement can be accurately predicted by a CNN using both static and dynamical correlators, even when the network is trained on only a fraction of the full dataset or on data from a different system than the one used for prediction. Specifically, when trained on observables from an anisotropic XY model, accurate predictions can be achieved using only about 3% (6%) of the data when employing dynamical two-point correlators (structure factors) for learning.
Contact : pierre.nataf@lpmmc.cnrs.fr

Soutenance de Thèse de Subham SENAPATI (IRIG / Spintec)
2026-03-11 14:00 - 16:00 | CEA – Salle de Séminaire IRIG (1005 – 445), Laboratoire Irig/Spintec, salle de séminaire 445, bâtiment 1005, CEA-Grenoble, Grenoble
Spin-orbit torque based magnetic memories evaluation for cryogenic applications
Résumé :
The rapid development of cryogenic computing platforms, including superconducting electronics, quantum information processors, high-performance computing systems, and space applications, has created a demand for memory technologies that operate efficiently, reliably, and scalable at low temperatures. While magnetic random-access memory (MRAM) is a mature and commercially deployed non-volatile memory at room temperature, its behaviour and limitations at cryogenic temperatures remain insufficiently explored, particularly for three-terminal spin-orbit torque magnetic tunnel junctions (SOT-MTJs). This thesis presents a comprehensive experimental and modelling study of SOT-based magnetic memories operated from room temperature (300 K) down to liquid-helium (4 K) temperatures. A dedicated cryogenic characterisation framework is developed to extract magnetic parameters, quantify switching statistics, and evaluate write performance under both quasi-static and sub-nanosecond pulsed conditions. Temperature-dependent measurements reveal enhanced magnetic anisotropy and thermal stability at low temperatures, accompanied by non-trivial trends in critical switching current. By combining experiments with micromagnetic simulations incorporating temperature-dependent material properties and transient Joule heating, this work demonstrates that self-heating remains a dominant factor during write operations, especially at cryogenic bath temperatures. Beyond conventional SOT-MRAM, complementary approaches including optimised spin-transfer torque devices and voltage-gate-assisted SOT switching are investigated. They show that controlling retention via storage layer thickness is a relevant strategy to decrease write current while electric-field control of anisotropy enables efficient modulation of switching across a large temperature range. Overall, this thesis establishes both the physical limitations and technological potential of SOT- and voltage-gated SOT-based MRAM as viable candidates for future cryogenic memory systems.
https://www.cea.fr/drf/irig/Pages/Animation-scientifique/theses/2026_Senapati.aspx
Contact : admin.spintec@cea.fr
