Classification of spin liquids with strong spin-orbit coupling

Datum

11.11.2015

Zeit

17:15 - 18:00

Sprecher

Johannes Reuther

Zugehörigkeit

FU Berlin

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

IMPRS Seminar

Beschreibung

Spin liquids are exotic types of quantum matter that do not develop any symmetry-breaking order even at zero temperature. In this talk I give an introduction to some basic properties of spin liquids such as fractional spinon excitations and topological ground-state degeneracies. Using a fermionic formalism for the spin operators I explain how spin liquids can be described by gauge theories. The concept of the "projective symmetry group" (PSG) method is introduced that allows one to classify different spin-liquid states based on a fermionic mean-field decoupling of the spin Hamiltonian. Particularly, I discuss the effects of spin-orbit coupling and show that a PSG classification of spin liquids in the case of broken SU(2) spin-rotation symmetry yields spin-liquids states with a topological spinon band structure. Hence, these states realize the remarkable situation where a non-trivial topology is implemented in two different ways, via the existence of deconfined spinon excitations and by a symmetry-protected topological spinon band structure.

Letztmalig verändert: 11.11.2015, 08:39:44