"Quantum valley Hall effect in graphene"

Ivar Martin

Los Alamos National Lab

Quantum Hall effect (QHE) is a remarkable macroscopic phenomenon that allows observation of quantized transverse conductivity in 2D metals in an applied magnetic field. The hallmark of QHE is the appearance on the chiral edge states, which are topologically protected (cannot back-scatter!) due to time-reversal symmetry breaking. Recently, there has been a lot of interest in quantum spin Hall effect, which doesn't require (and in fact is destroyed by!) time-reversal breaking, e.g. magnetic field or magnetic impurities. In this talk I will introduce the quantum valley Hall (QVHE) effect in graphene-like materials and will describe its connection to the charge and spin quantum Hall effects. I will discuss the consequences for experiments on bilayer graphene, as well as possible applications.