Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 18: Correlated Electrons: Spin Systems and Itinerant Magnets – Frustrated Magnets 2 (jointly with MA)

TT 18.5: Vortrag

Montag, 16. März 2015, 16:00–16:15, H 3005

Majorana metals and quantum spin liquids — •Maria Hermanns, Kevin O'Brien, and Simon Trebst — Institute for Theoretical Physics, Cologne, Germany

One of the most intriguing phenomena in strongly correlated systems is the fractionalization of quantum numbers -- familiar examples include the spin-charge separation in one-dimensional metallic systems, the fractionalization of the electron in fractional quantum Hall states or the emergence of monopoles in spin ice.

In this talk, I will discuss the fractionalization of magnetic moments in spin-orbit entangled j=1/2 Mott insulators, in which the emergent degrees of freedom are Majorana fermions. The latter form metallic states whose precise character intimately depends on the underlying lattice structure. The origin of such dichotomous states is elucidated by a family of exactly solvable Kitaev-type models of frustrated quantum magnets in three dimensions, which might be realized in a class of recently synthesized Iridate compounds. In particular, these models provide the first analytical tractable examples of long sought-after quantum spin liquids with a spinon Fermi surface and even an entire new class of quantum spin liquids -- so-called Weyl spin liquids, in which the fractionalized degrees of freedom form a topological Weyl-superconductor.