Publication

Symmetric and asymmetric excitations of a strong-leg quantum spin ladder

Publications associées (30)

Many-body physics with strongly interacting fermions coupled to light

This thesis reports on the realization of the first experiments conducted with superfluid, strongly interacting Fermi gases of 6Li coupled to the light field of an optical cavity. In the scope of existing ultracold atomic platforms, this is the first time ...

EPFL2023

Real space and reciprocal space investigations of the spin dynamics in skyrmion-hosting materials

Le Yu

Magnetic skyrmions are whirl-like spin configurations with particle-like properties protected by non-trivial topology. Due to their unique spin structures and dynamical properties, they have attracted tremendous interests over the past decade, from fundame ...

EPFL2022

Influence of static correlation on the magnon dynamics of an itinerant ferromagnet with competing exchange interactions: First-principles study of MnBi

Henrik Moodysson Rønnow, Thorbjørn Skovhus

We present first-principles calculations of the dynamic susceptibility in strained and doped ferromagnetic MnBi using time-dependent density functional theory. In spite of being a metal, MnBi exhibits signatures of strong correlation and a proper descripti ...

AMER PHYSICAL SOC2022

Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr14-xCaxCu24O41 ladders

Henrik Moodysson Rønnow, Yi Tseng, Thorsten Schmitt

We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr14-xCaxCu24O41 (SCCO) using Cu L-3-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without ( ...

NATURE PORTFOLIO2022

Thermal Evolution of Dirac Magnons in the Honeycomb Ferromagnet CrBr3

Andreas Martin Läuchli Herzig, Bruce Normand, Christian Rüegg

CrBr3 is an excellent realization of the two-dimensional honeycomb ferromagnet, which offers a bosonic equivalent of graphene with Dirac magnons and topological character. We perform inelastic neutron scattering measurements using state-of-the-art instrume ...

2022

Lack of Out-of-Plane Dispersion of the Magnetic Excitations of Charge-Stripe Ordered La2−xSrxNiO4+δ

Paul Gregory Freeman, Alexandra Angeline Turrini

The dependence of the magnetic excitations in the out-of-NiO-plane direction of charge stripe ordered La2-xSrxNiO4+delta x = 0.3 and delta = 0.11 +/- 0.01 were investigated by inelastic neutron scattering. No dispersion was observed for the magnetic excita ...

Physical Soc Japan2022

Investigating field-induced magnetic order in Han purple by neutron scattering up to 25.9 T

Philippe Heller, Frédéric Mila, Bruce Normand, Nicolas Laflorencie

BaCuSi2O6 is a quasi-two-dimensional (2D) quantum antiferromagnet containing three different types of stacked, square-lattice bilayer hosting spin-1/2 dimers. Although this compound has been studied extensively over the last two decades, the critical appli ...

2022

Static and dynamic properties of non-collinear quantum antiferromagnets explored by neutron scattering

Luc Testa

This thesis is devoted to the investigation of static and dynamic properties of two different sets of quantum magnets with neutron scattering techniques and the help of linear spin wave theory. Both systems are copper-based with spin-1/2, which makes them ...

EPFL2021

Order and dynamics in Kagome like compound Cu2OSO4 and other quantum magnets

Virgile Yves Favre

This thesis presents results of studies of novel compounds modeling complex fundamental physics phenomena. Cu2OSO4 is a copper based magnetic Mott Insulator system, where spin half magnetic moments form a new type of lattice. These intrinsically quantum pi ...

EPFL2021

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

Superexchange mechanism and quantum many body excitations in the archetypal di-Cu oxo-bridge

Cédric Weber, Edward Baxter Linscott

The hemocyanin protein binds and transports molecular oxygen via two copper atoms at its core. The singlet state of the Cu2O2 core is thought to be stabilised by a superexchange pathway, but detailed in situ computational analysis is complicated by the mul ...

NATURE PUBLISHING GROUP2020

Temperature dependence of the(pi,0)anomaly in the excitation spectrum of the 2D quantum Heisenberg antiferromagnet

Martin Mourigal, Henrik Moodysson Rønnow, Goran Nilsen

It is well established that in the low-temperature limit, the two-dimensional quantum Heisenberg antiferromagnet on a square lattice (2DQHAFSL) exhibits an anomaly in its spectrum at short-wavelengths on the zone-boundary. In the vicinity of the (pi, 0) po ...

IOP PUBLISHING LTD2020

Structural characterization and magnetic properties of chromium jarosite KCr3(OD)(6)(SO4)(2)

Sofie Janas

Potassium chromium jarosite, KCr3(OH)(6)(SO4)(2) (Cr-jarosite), is considered a promising candidate to display spin liquid behavior due to the strong magnetic frustration imposed by the crystal structure. However, the ground state magnetic properties have ...

ROYAL SOC CHEMISTRY2020

Interacting Dirac materials

Gabriel Aeppli

We investigate the extent to which the class of Dirac materials in two-dimensions provides general statements about the behavior of both fermionic and bosonic Dirac quasiparticles in the interacting regime. For both quasiparticle types, we find common feat ...

2020

Large charge, semiclassics and superfluids : from broken symmetries to conformal field theories

Gabriel Francisco Cuomo

This thesis explores the application of semiclassical methods in the study of states with large quantum numbers for theories invariant under internal symmetries. In the first part of the thesis, we study zero-temperature superfluids. These provide a gener ...

EPFL2020

Scale-invariant magnetic anisotropy in RuCl(3)at high magnetic fields

Philip Johannes Walter Moll, Maja Deborah Bachmann

Scale-invariant magnetic anisotropy in RuCl(3)has been revealed through measurements of its magnetotropic coefficient, providing evidence for a high degree of exchange frustration that favours the formation of a spin liquid state. In RuCl3, inelastic neutr ...

2020

Wave Vector Difference of Magnetic Bragg Reflections and Low Energy Magnetic Excitations in Charges-tripe Ordered La2NiO4.11

Paul Gregory Freeman

We report on the magnetism of charge-stripe ordered La2NiO4.11 +/- 0.01 by neutron scattering and mu SR. On going towards zero energy transfer there is an observed wave vector offset in the centring of the magnetic excitations and magnetic Bragg reflection ...

Nature Research2019

Elementary excitation in the spin-stripe phase in quantum chains

Helmuth Berger, Jonathan White

Elementary excitations in condensed matter capture the complex many-body dynamics of interacting basic entities in a simple quasiparticle picture. In magnetic systems the most established quasiparticles are magnons, collective excitations that reside in or ...

Springer2019

Orbitally selective breakdown of Fermi liquid quasiparticles in Ca1.8Sr0.2RuO4

Marco Grioni, Johan Juul Chang, Gianmarco Gatti

We present a comprehensive angle-resolved photoemission spectroscopy study of Ca1.8Sr0.2RuO4. Four distinct bands are revealed and along the Ru-O bond direction their orbital characters are identified through a light polarization analysis and comparison to ...

AMER PHYSICAL SOC2019

Exact diagonalization study of the Hubbard-parametrized four-spin ring exchange model on a square lattice

Henrik Moodysson Rønnow, Noore Elahi Shaik, Sofie Janas

We have used exact numerical diagonalization to study the excitation spectrum and the dynamic spin correlations in the s = 1/2 next-next-nearest-neighbor Heisenberg antiferromagnet on the square lattice, with additional four-spin ring exchange from higher- ...

AMER PHYSICAL SOC2019