Alex Frano (SIMES Seminar)

Date/Time
Date(s) - May 20 2016
11:00 AM - 12:00 PM

Location
Sierra Room, Bldg 40, Room R125

Category(ies)


 

Hidden magnetic order in the Kitaev honeycomb iridate Li2IrO3

Alex Frano

Postdoc at LBL (Materials Science Division/Advanced Light Source)
Lawrence Berkeley Lab, Berkeley

 

Correlated electron systems with sizable spin-orbit coupling have emerged as candidates to realize exotic electronic and magnetic ground states.  Arranging 5d-iridates in a honeycomb lattice, in the presence of an octahedral crystal electric field, was suggested as a route to realize a peculiar (j=1/2) isospin-anisotropic magnetic interaction. As first observed theoretically by Kitaev, the resulting frustrated, bond-directional interaction could host a highly degenerate, quantum spin liquid (QSL) ground state. Indeed each of the honeycomb-iridate compounds A2IrO3 (A=Na,Li) exhibits its own kind of low-temperature magnetic order, which are believed to surround the QSL phase. However, evidence of true magnetic ground state degeneracy has been absent.  In this talk, we will show how applying a magnetic field to Li2IrO3 “lights up” a hidden magnetic phase that coexists with a zero-field, incommensurate spiral order.  Using resonant x-ray diffraction we can untangle the two phases in reciprocal space and show that the system displays magnetic degeneracy indicative of a nearby QSL.