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Non-Equilibrium Aspects of Floquet Chern Insulators

May 30, 2018 - 10:00am
Speaker: 
Hossein Dehghani
Institution: 
New York University

Abstract: During the last decade, it has been demonstrated that topological structures in condensed matter systems may be realized under non-equilibrium conditions where external time-dependent perturbations represent a rich and versatile resource that can be used to achieve topological properties.  Specifically, periodic driving may give rise to new Hamiltonians with non-trivial topological insulator spectra, known as Floquet topological/Chern insulators (FTIs). However, being driven these systems are far out of equilibrium and have unique non-equilibrium aspects that must be taken into account in any realistic setting.

In this talk, I review some of the highlights of our previous works on non-equilibrium aspects of these systems under closed quench, and open dissipative non-equilibrium protocols where we demonstrate that the system is described by non-thermal steady states.  The specific model studied here is a hexagonal lattice such as graphene, under the irradiation of circularly polarized laser fields.  I review our theoretical predictions for experimentally measurable quantities including the angle-resolved photoemission spectroscopy (ARPES), and the DC Hall conductance.  Finally, in presence of a quench electron-electron interaction and periodic driving the possibility of a superconducting phase transition in a hexagonal lattice at the mean field level is investigated.

Host: Mohammad Hafezi

PSC 2148