Publications associées à Mer de Dirac

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

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

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

Experimental Observation and Spin Texture of Dirac Node Arcs in Tetradymite Topological Metals

Emmanouil Frantzeskakis, Ji Dai

We report the observation of a nontrivial spin texture in Dirac node arcs, i.e., novel topological objects formed when Dirac cones of massless particles extend along an open one-dimensional line in momentum space. We find that such states are present in al ...

AMER PHYSICAL SOC2021

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2As2

Joël Mesot, Vladimir N. Strocov, Pierre Richard, Han Wang, Hang Li

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realizatio ...

Wiley-V C H Verlag Gmbh2020

Two-dimensional Rashba metals: Unconventional low-temperature transport properties

Claudio Grimaldi

Rashba spin-orbit coupling emerges in materials lacking of structural inversion symmetry, such as heterostructures, quantum wells, surface alloys and polar materials, just to mention few examples. It yields a coupling between the spin and momentum of elect ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Efficient Multi-dimensional Diracs Estimation with Linear Sample Complexity

Martin Vetterli, Thierry Blu, Hanjie Pan

Estimating Diracs in continuous two or higher dimensions is a fundamental problem in imaging. Previous approaches extended one dimensional methods, like the ones based on finite rate of innovation (FRI) sampling, in a separable manner, e.g., along the hori ...

2018

Band and Correlated Insulators of Cold Fermions in a Mesoscopic Lattice

Jean-Philippe Brantut, Thierry Giamarchi, Samuel Häusler

We investigate the transport properties of neutral, fermionic atoms passing through a one-dimensional quantum wire containing a mesoscopic lattice. The lattice is realized by projecting individually controlled, thin optical barriers on top of a ballistic c ...

American Physical Society2018

Evolution of the Fermi surface of BiTeCl with pressure

Helmuth Berger

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeCl under applied pressures up to similar to 2.5 GPa. We observe two distinct oscillation frequencies, corresponding to the Rashba-split inner and outer Fermi sur ...

Iop Publishing Ltd2017

The classical and quantum dynamics of molecular spins on graphene

Klaus Kern, Marko Burghard, Stephan Rauschenbach

Controlling the dynamics of spins on surfaces is pivotal to the design of spintronic(1) and quantum computing(2) devices. Proposed schemes involve the interaction of spins with graphene to enable surface-state spintronics(3,4) and electrical spin manipulat ...

Nature Publishing Group2016

Germanene: the germanium analogue of graphene

Magalí Alejandra Lingenfelder, Lei Zhang, Adil Acun

Recently, several research groups have reported the growth of germanene, a new member of the graphene family. Germanene is in many aspects very similar to graphene, but in contrast to the planar graphene lattice, the germanene honeycomb lattice is buckled ...

Institute of Physics2015

Pressure tuning the Fermi level through the Dirac point of giant Rashba semiconductor BiTeI

Helmuth Berger

We report measurements of Shubnikov-de Haas oscillations in the giant Rashba semiconductor BiTeI under applied pressures up to similar to 2GPa. We observe one high frequency oscillation at all pressures and one low frequency oscillation that emerges betwee ...

Iop Publishing Ltd2014

Dirac Structures, Nonholonomic Systems And Reduction

Tudor Ratiu, Madeleine Jotz

The reduction of nonholonomic systems is formulated in terms of Dirac reduction. An optimal reduction method for a class of nonholonomic systems is formulated. Several examples are studied in detail. ...

Elsevier2012

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

Spin-Orbital Quantum Liquid on the Honeycomb Lattice

Frédéric Mila, Karlo Penc, Miklos Lajko

The main characteristic of Mott insulators, as compared to band insulators, is to host low-energy spin fluctuations. In addition, Mott insulators often possess orbital degrees of freedom when crystal-field levels are partially filled. While in the majority ...

American Physical Society2012

Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3

Klaus Kern, Marco Grioni, Helmuth Berger, Philippe Bugnon, Alberto Crepaldi

We exploit time- and angle-resolved photoemission spectroscopy to determine the evolution of the out-of-equilibrium electronic structure of the topological insulator Bi2Se3. The response of the Fermi-Dirac distribution to ultrashort IR laser pulses has bee ...

Amer Physical Soc2012

Induced Dirac structures on isotropy-type manifolds

Tudor Ratiu, Madeleine Jotz

A new method of singular reduction is extended from Poisson to Dirac manifolds. Then it is shown that the Dirac structures on the strata of the quotient coincide with those of the only other known singular Dirac reduction method. ...

Birkhäuser-Verlag, Springer2011

Singular Reduction Of Dirac Structures

Tudor Ratiu, Madeleine Jotz

The regular reduction of a Dirac manifold acted upon freely and properly by a Lie group is generalized to a nonfree action. For this, several facts about G-invariant vector fields and one-forms are shown. ...

2011

Helical fluctuations in the Raman response of the topological insulator Bi2Se3

Helmuth Berger, Kazimierz Conder

The topological insulator Bi2Se3 shows a Raman-scattering (RS) response related to topologically protected surface states amplified by a resonant interband transition. Most significantly this signal has a characteristic Lorentzian lineshape and spin-helica ...

2011

Dirac Group(oid)s and Their Homogeneous Spaces

Madeleine Jotz

A theorem of Drinfel'd (Drinfel'd (1993)) classifies the Poisson homogeneous spaces of a Poisson Lie group (G,πG) via a special class of Lagrangian subalgebras of the Drinfel'd double of its Lie bialgebra. This result is extended in Liu et al. (1998) to a ...

EPFL2011

Selective adsorption and electronic interaction of F16CuPc on epitaxial graphene

Efthimios Kaxiras, Sheng Meng, Jun Ren, Xi Chen

We investigate the electronic coupling between copper hexadecafluoro-phthalocyanine (F16CuPc) and epitaxial graphene (EG) on 6H-SiC (0001) using a combined approach of low-temperature scanning tunneling spectroscopy and electronic structure calculations. T ...

2010