Publications related to Orbiton

Nonlinear optical diode effect in a magnetic Weyl semimetal

Philip Johannes Walter Moll, Chunyu Guo, Hao Yang

Diode effects are of great interest for both fundamental physics and modern technologies. Electrical diode effects (nonreciprocal transport) have been observed in Weyl systems. Optical diode effects arising from the Weyl fermions have been theoretically co ...

Nature Portfolio2024

Unconventional Flat Chern Bands and 2e Charges in Skyrmionic Moire Superlattices

Oleg Yazyev, Yifei Guan

The interplay of topological characteristics in real space and reciprocal space can lead to the emergence of unconventional topological phases. In this Letter, we implement a novel mechanism for generating higher-Chern flat bands on the basis of twisted bi ...

AMER CHEMICAL SOC2023

Hole-induced anomaly in the thermodynamic behavior of a one-dimensional Bose gas

Riccardo Rota

We reveal an intriguing anomaly in the temperature dependence of the specific heat of a one-dimensional Bose gas. The observed peak holds for arbitrary interaction and remembers a superfluid-to-normal phase transition in higher dimensions, but phase transi ...

SCIPOST FOUNDATION2022

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

Spinon confinement and deconfinement in spin-1 chains

Frédéric Mila, Natalia Chepiga, Elisabeth Wybo

Motivated by the rich phase diagrams recently unveiled in frustrated spin-1 chains with competing next-nearest-neighbor and four-spin interactions, we investigate the nature of the elementary excitations of spin-1 chains in the vicinity of phase transition ...

2020

Coexisting spinons and magnons in the frustrated zigzag spin-1/2 chain compound beta-TeVO4

Helmuth Berger

We investigate magnetic excitations in the frustrated zigzag spin-1/2 chain compound beta-TeVO4 by inelastic neutron scattering. In the magnetically ordered ground state, the excitation spectrum exhibits coexisting magnon dispersion, characteristic of long ...

AMER PHYSICAL SOC2018

Probing multi-spinon excitations outside of the two-spinon continuum in the antiferromagnetic spin chain cuprate Sr2CuO3

Henrik Moodysson Rønnow, Martin Mourigal, Thorsten Schmitt

One-dimensional (1D) magnetic insulators have attracted significant interest as a platform for studying quasiparticle fractionalization, quantum criticality, and emergent phenomena. The spin-1/2 Heisenberg chain with antiferromagnetic nearest neighbour int ...

Nature Research2018

Kinetic Monte Carlo approach to nonequilibrium bosonic systems

Timothy Chi Hin Liew, Hugo Pierre Alexandre Flayac

We consider the use of a kinetic Monte Carlo approach for the description of nonequilibrium bosonic systems, taking nonresonantly excited exciton-polariton condensates and bosonic cascade lasers as examples. In the former case, the considered approach allo ...

Amer Physical Soc2017

Multivalley engineering in semiconductor microcavities

Hugo Pierre Alexandre Flayac, Timothy Chi Hin Liew

We consider exciton-photon coupling in semiconductor microcavities in which separate periodic potentials have been embedded for excitons and photons. We show theoretically that this system supports degenerate ground-states appearing at non-zero inplane mom ...

Springer Nature2017

Magnons in tetragonal CuO

Henrik Moodysson Rønnow, Frédéric Mila, Marco Grioni, Simon Karl Moser, Thorsten Schmitt, Bastien Dalla Piazza, Sara Fatale, Noore Elahi Shaik

We investigate by resonant inelastic x-ray scattering the magnetic excitations in thin films of tetragonal CuO. We identify a spin wave excitation, dispersing on two cupratelike antiferromagnetic sublattices. Its energy at the boundary of the Brillouin zon ...

2015

Noise-Induced Phenomena in Collective Spinor Polariton Excitations

Hadis Abbaspour

Polaritons are quasiparticles resulting from the strong coupling between photons and excitons embedded in a semiconductor microcavity. The exciton component of polaritons provides strong nonlinear interactions, while their photonic counterpart facilitates ...

EPFL2015

Direct measurement of the bulk spin structure of noncentrosymmetric BiTeCl

Jan Hugo Dil, Stefan Peter Muff

A strong spin-orbit interaction leads to a Rashba-type splitting of the bulk bands of BiTeCl, which results in toroidal Fermi surfaces with distinct spin structures depending on the chemical potential. Here, we present spin-and angle-resolved photoelectron ...

American Physical Society2015

Nonlinear relaxation and selective polychromatic lasing of confined polaritons

Benoît Marie Joseph Deveaud, Gabriele Grosso, François Morier-Genoud, Marcia Portella Oberli, Stéphane Trebaol

Polaritons have often been proposed as promising candidates for the realization of all-optical devices due to the easy manipulation and control of their density and spin. In this paper we present a relaxation mechanism for confined polaritons and its appli ...

Amer Physical Soc2014

Koopmans-compliant functionals and their performance against reference molecular data

Nicola Marzari, Giovanni Borghi, Andrea Ferretti

Koopmans-compliant functionals emerge naturally from extending the constraint of piecewise linearity of the total energy as a function of the number of electrons to each fractional orbital occupation. When applied to approximate density-functional theory, ...

Amer Physical Soc2014

Bridging density-functional and many-body perturbation theory: Orbital-density dependence in electronic-structure functionals

Nicola Marzari, Matteo Cococcioni, Andrea Ferretti

Energy functionals which depend explicitly on orbital densities, rather than on the total charge density, appear when applying self-interaction corrections to density-functional theory; this is, e.g., the case for Perdew-Zunger and Koopmans-compliant funct ...

Amer Physical Soc2014

Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain

Henrik Moodysson Rønnow, Martin Mourigal, Jean-Sebastien Caux, Mechthild Enderle

One of the simplest quantum many-body systems is the spin-1/2 Heisenberg antiferromagnetic chain, a linear array of interacting magnetic moments. Its exact ground state is a macroscopic singlet entangling all spins in the chain. Its elementary excitations, ...

Nature Publishing Group2013

Interplay of Dirac fermions and heavy quasiparticles in solids

Thorsten Schmitt

Many-body interactions in crystalline solids can be conveniently described in terms of quasiparticles with strongly renormalized masses as compared with those of non-interacting particles. Examples of extreme mass renormalization are on the one hand graphe ...

Nature Publishing Group2013

Magnetization States of All-Oxide Spin Valves Controlled by Charge-orbital Ordering of Coupled Ferromagnets

Charge-orbital ordering is commonly present in complex transition metal oxides and offers interesting opportunities for novel electronic devices. In this work, we demonstrate for the first time that the magnetization states of the spin valve can be directl ...

Nature Publishing Group2013

Spin-orbital separation in the quasi-one-dimensional Mott insulator Sr2CuO3

Henrik Moodysson Rønnow, Martin Mourigal, Thorsten Schmitt, Jean-Sebastien Caux

When viewed as an elementary particle, the electron has spin and charge. When binding to the atomic nucleus, it also acquires an angular momentum quantum number corresponding to the quantized atomic orbital it occupies. Even if electrons in solids form ban ...

2012

Anomalously enhanced photoemission from the Dirac point and other peculiarities in the self-energy of the surface-state quasiparticles in Bi2Se3

Helmuth Berger

Line-shape analysis of the photoemission intensity from the surface states of Bi2Se3 reveals two unusual features: spectral line asymmetry and anomalously enhanced photoemission from the Dirac point. The former can be described by the one-particle spectral ...

2012