Dyon condensation in topological Mott insulators

We consider quantum phase transitions out of topological
Mott insulators in which the ground state of the fractionalized excitations
(fermionic spinons) is topologically non-trivial. The spinons in topological
Mott insulators are coupled to an emergent compact U(1) gauge field with a
so-called "axion" term. We study the confinement transitions from the
topological Mott insulator to broken symmetry phases, which may occur via the
condensation of dyons. Dyons carry both "electric" and
"magnetic" charges, and arise naturally in this system because the
monopoles of the emergent U(1) gauge theory acquires gauge charge due to the
axion term. It is shown that the dyon condensate, in general, induces
simultaneous current and bond orders. When the magnetic transition is driven by
dyon condensation, we identify the bond order as valence bond solid order and
the current order as scalar spin chirality order. Hence, the confined phase of
the topological Mott insulator is an exotic phase where the scalar spin chirality
and the valence bond order coexist and appear via a single transition.


If time allows, I will also discuss our recent work on
the proximate symmetry-broken phases of Z2 spin liquid on Kagome lattice.

Event Type: 
Scientific Area(s): 
Event Date: 
Wednesday, November 28, 2012 - 15:30 to 17:00
Bob Room
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