Início
Agenda 

 05 de julho de 2017
16h30 Sala
146 (LEF) 

Willian
M. H. Natori

IFSC


Dynamics
of a j =3/2 quantum spin liquid


Mott insulators that retain orbital degeneracy and
display strong spinorbit coupling (SOC) are a new focus of
research in the field of strongly correlated systems. Most of
this interest is traced back to the seminal work of Jackeli and
Khaliullin [1], who showed that the interplay of lattice
geometry and SOC in specific transition metal compounds
generates a solid state platform to the exactly solvable Kitaev
model [2]. One can show through a simple Majorana fermion
representation that this j=1/2 spin model has a quantum spin
liquid (QSL) ground state with Majorana fermions and vison
excitations. The line of research opened by Ref. [1] has proved
very fruitful to discover new and exotic magnetic phases.
Unfortunately, the studies also showed that the Kitaev QSL is
not sufficiently stable to usual realistic perturbations. In
this Colloquium, I will present an alternative way to search for
QSLs using the JackeliKhaliullin mechanism to derive j=3/2
exchangefrustrated spinorbital models. Then, I propose a
Majorana QSL [3] in analogy with Kitaev's work and analyze its
experimental responses [4]. In this seminar, I focus on the
resonant inelastic xray scattering (RIXS) results. I will show
how symmetry arguments can be used to link photonpolarization
factors and RIXS probed excitations. It is then proved that RIXS
cross sections supply important information of j=3/2 systems
that remain hidden in neutron scattering. Comparison between
theoretical and experimental results of the QSL candidate
Ba2YMoO6 will be shown. In the end of the seminar I will give
perspectives for this field, both in theory and experiments.


[1] G. Jackeli and G. Khaliullin. PRL, 102, 017205
(2009)

[2] A. Kitaev. Ann. Phys., 321, 2 (2006)

[3] W. M. H. Natori, E. C. Andrade, E. Miranda, and
R. G. Pereira., PRL, 117, 017204 (2016)

[4] W. Natori, M. Daghofer, and R. Pereira., ArXiv
eprints, 1704.06134 (2017).




