Majorana fermions in the Kitaev honeycomb magnet
Vendredi 30 novembre 2018 10:00
- Duree : 1 heure
Lieu : Salle « Remy Lemaire » (K223) de l’Institut Néel – au n°25 de la rue des martyrs, Grenoble.
Orateur : Martin KLANJSEK (Jožef Stefan Institute, Ljubljana)
Quantum spin liquid is a disordered but highly-entangled magnetic state with fractional spin excitations. The most common type of fractional spin excitations are fermionic spinons, well known from one- and some two-dimensional quantum magnets. In the exactly solved Kitaev honeycomb spin model, a spin instead fra ctionalizes into two types of anyonic quasiparticles : a pair of gauge fluxes and a Majorana fermion [1]. I will present a nuclear magnetic resonance experiment on the most promising Kitaev magnet α-RuCl3 that allowed us to observe two contributions to the spin excitation gap [2] : a finite zero-field contribution, which matches the predicted size of the gauge-flux gap, and a theoretically predicted contribution growing as a cube of the applied magnetic field, which is a hallmark of Majorana fermions [1]. As both types of fractional excitations survive in a broad range of temperatures and magnetic fields, α-RuCl3 is perfectly suited for future investigations of Majorana fermions.
[1] A. Kitaev, Ann. Phys. 321, 2 (2006).
[2] N. Janša, A. Zorko, M. Gomilšek, M. Pregelj, K. W. Krämer, D. Biner, A. Biffin, Ch. Rüegg, and M. Klanjšek, Nature Physics 14, 786 (2018).
Contact : elsa.lhotel@neel.cnrs.fr
Discipline évènement : (Physique)
Entité organisatrice : (Institut Néel / MCBT)
Nature évènement : (Séminaire)
Site de l'évènement : Polygone scientifique
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