VietNam 2013 

IXth Rencontres du Vietnam
Quy-Nhon, August 4-10, 2013


 Nanophysics: from fundamentals to applications

(the return)


Wednesday 7

› 14:00 - 14:20 (20min)
Graphene Induced Topological Insulator (Topological order and Superconductivity)
Cyril Petitjean  1@  
1 : ENS de Lyon
ENS Lyon
Laboratoire de Physique ENS Lyon 46, Allée d'Italie Lyon F-69007 -  France

Two-dimensional topological insulators are commonly referred to as quantum spin-Hall (QSH) states. Contrary to the three-dimensional topological insulators that have been found to abound in nature, the two-dimensional are rather limited. However recently a spin-orbit induced QSH phase has been proposed. The key ingredient is the use of indium adatoms deposited on the surface of graphene thats should turn the latter into a QSH insulator characterized by a sizable gap. This artificial QSH system present strong potentials applications (thermopower, spintronics device,...) 
One interesting fact about indiums is that the latter becomes superconductor at low enough temperature. Therefore the graphene+indium artificial QSH system becomes a promising candidate to study the competition between induced superconductivity and the spin-orbit coupling.

In this talk, we will first give a short introduction on the two-dimensional topological insulators and the related artificial QSH system. We then finally turn on the superconducting order and spin-orbit competition and show that starting form a general superconducing plaquette interaction, the latter can be reduced to a simpler effective model. This permit us to determine the first preliminary phase diagram.

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