Publications associées à Composition dependence of spin transition in (Mg,Fe)SiO3 bridgmanite

New tools for phase segmentation and denoising of analytical STEM data for enhanced chemical sensitivity, applied to Earth mantle research

This thesis is dedicated to developing innovative methodologies that improve elemental quantification in scanning transmission electron microscopy (STEM) using energy-dispersive X-ray spectroscopy (EDXS). The primary motivation stems from a geochemistry pr ...

EPFL2023

Numerical investigation of bound states in quantum magnets

Mithilesh Nayak

Bound-states of particles are an interesting problem in quantum mechanics dating back to 1931 Bethe's solution of spin-1/2 Heisenberg chain. These exotic composite states are realized in quantum magnets and are detectable in inelastic neutron scattering (I ...

EPFL2023

Magnon-phonon interactions enhance the gap at the Dirac point in the spin-wave spectra of CrI3 two-dimensional magnets

Iurii Timrov

Recent neutron-diffraction experiments in honeycomb CrI3 quasi-2D ferromagnets have evinced the existence of a gap at the Dirac point in their spin-wave spectra. The existence of this gap has been attributed to strong in-plane Dzyaloshinskii-Moriya or Kita ...

2023

First-principles study of the gap in the spin excitation spectrum of the CrI3 honeycomb ferromagnet

Iurii Timrov

The nature of the gap observed at the zone border in the spin excitation spectrum of CrI3 quasitwo-dimensional single crystals is still controversial. We perform first-principles calculations based on time-dependent density functional perturbation theory, ...

Amer Physical Soc2023

Momentum-resolved spin-conserving two-triplon bound state and continuum in a cuprate ladder

Henrik Moodysson Rønnow, Yi Tseng, Thorsten Schmitt, Vladimir N. Strocov

Studying multi-particle elementary excitations has provided unique access to understand collective many-body phenomena in correlated electronic materials, paving the way towards constructing microscopic models. In this work, we perform O K-edge resonant in ...

NATURE PORTFOLIO2023

Large Orbital Moment of Two Coupled Spin-Half Co Ions in a Complex on Gold

Stefano Rusponi, Chao Li, Boris Sorokin

The magnetic propertiesof transition-metal ions aregenerallydescribed by the atomic spins of the ions and their exchange coupling.The orbital moment, usually largely quenched due the ligand field,is then seen as a perturbation. In such a scheme, S = 1/2 io ...

AMER CHEMICAL SOC2023

First-Principles Thermodynamics of CsSnI3

Nicola Marzari, Lorenzo Monacelli

CsSnI3 is a promising ecofriendly solution for energy harvesting technologies. It exists at room temperature in either a black perovskite polymorph or a yellow 1D double-chain, which irreversibly deteriorates in the air. In this work, we unveil the relativ ...

AMER CHEMICAL SOC2023

Carbon K-edge x-ray emission spectroscopy of gas phase ethylenic molecules

Majed Chergui, Luca Longetti, Thomas Roland Barillot, Camila Bacellar Cases Da Silveira, Rebecca Ann Ingle

We report on the C K-edge x-ray absorption spectra and the resonant (RXES) and non-resonant (NXES) x-ray emission spectra of ethylene, allene and butadiene in the gas phase. The RXES and NXES show clear differences for the different molecules. Overall both ...

IOP Publishing2022

Fully Tunable Longitudinal Spin-Photon Interactions in Si and Ge Quantum Dots

Pasquale Scarlino

Spin qubits in silicon and germanium quantum dots are promising platforms for quantum computing, but entangling spin qubits over micrometer distances remains a critical challenge. Current prototypical architectures maximize transversal interactions between ...

AMER PHYSICAL SOC2022

turboMagnon - A code for the simulation of spin-wave spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory

Iurii Timrov

We introduce turboMagnon, an implementation of the Liouville-Lanczos approach to linearized time-dependent density-functional theory, designed to simulate spin-wave spectra in solid-state materials. The code is based on the noncollinear spin-polarized fram ...

ELSEVIER2022

Ultrafast X-ray Spectroscopy of Haem Proteins

Majed Chergui, Camila Bacellar Cases Da Silveira

In this article we revisit our recent picosecond and femtosecond X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) experiments, probing the ultrafast electronic and geometric evolution of photoexcited haem proteins, namely ferrous N ...

SWISS CHEMICAL SOC2022

Magnetic Properties of Surface Adsorbed Metal Adatoms and Dimers

Dante Philippe Sblendorio

This thesis investigates the magnetic properties of single atoms and dimers adsorbed on graphene and oxide decoupling layers supported by single crystal metal substrates, using scanning tunneling microscopy (STM) and spin-polarized scanning tunneling micro ...

EPFL2022

Possibility to detect the bound state of the Heisenberg ferromagnetic chain at intermediate temperature

Frédéric Mila, Mithilesh Nayak

Motivated by the lack of direct evidence with inelastic neutron scattering of the well documented bound state of Heisenberg ferromagnets, we use the time-dependent thermal density matrix renormalization group algorithm to study the temperature dependence o ...

2022

Investigating Magma Ocean Solidification on Earth Through Laser‐Heated Diamond Anvil Cell Experiments

Marco Cantoni, Cécile Hébert, Philippe Gillet, Farhang Nabiei, James Badro, Charles-Edouard Boukaré

We carried out a series of silicate fractional crystallization experiments at lower mantle pressures using the laser-heated diamond anvil cell. Phase relations and the compositional evolution of the cotectic melt and equilibrium solids along the liquid lin ...

2021

Composition and Pressure Effects on Partitioning of Ferrous Iron in Iron-Rich Lower Mantle Heterogeneities

Marco Cantoni, Philippe Gillet, Farhang Nabiei, Susannah McGregor Dorfman, James Badro, Charles-Edouard Boukaré

Both seismic observations of dense low shear velocity regions and models of magma ocean crystallization and mantle dynamics support enrichment of iron in Earth’s lowermost mantle. Physical properties of iron-rich lower mantle heterogeneities in the modern ...

2021

The Effects of Planetary and Stellar Parameters on Brittle Lithospheric Thickness

Marie Estelle Solange Violay, Michael Heap

The thicknesss of the brittle lithosphere—the outer portion of a planetary body that fails via fracturing— plays a key role in the geological processes of that body. The properties of both a planet and its host star can influence that thickness, and the po ...

2021

Resonant Inelastic X-ray Scattering Studies of Low-Dimensional and Frustrated 3d Transition-Metal Oxides

Yi Tseng

3d transition-metal oxide materials with strong electron correlations and low dimensionality give rise to emerging exotic phases. Resonant inelastic X-ray scattering (RIXS) has developed as a powerful spectroscopic tool for probing the collective excitatio ...

EPFL2021

Tuning interactions in reconfigurable kagome artificial spin ices for magnonics

Dirk Grundler, Vinayak Shantaram Bhat

We report broadband spin-wave spectroscopy on kagome artificial spin ices (KASIs) made of large arrays of disconnected Ni81Fe19 400-nm-long nanobars. We observed spin wave spectra that varied characteristically upon the separation between neighboring nanob ...

AIP American Institute of Physics2021

Quantum dynamics in individual surface spins

Tobias Bilgeri

This thesis presents a combined experimental and theoretical study of the classical and quantum magnetization dynamics in single magnetic adatoms and molecules, and on the classical and quantum coherent control thereof. First, a detailed description of t ...

EPFL2021

Effects of composition and pressure on electronic states of iron in bridgmanite

Arnaud Magrez, Philippe Gillet, Susannah McGregor Dorfman

Electronic states of iron in the lower mantle's dominant mineral, (Mg,Fe,Al)(Fe,Al,Si)O-3 bridgmanite, control physical properties of the mantle including density, elasticity, and electrical and thermal conductivity. However, the determination of electroni ...

MINERALOGICAL SOC AMER2020