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Jeudi 05 Mai 2011, 16h00
Amphi Boreau, Esc C, 2ème etage
A recipe for turning graphene into a robust topological insulator using adatoms
Jason Alicea
University of California, Irvine
The 2007 discovery of quantized electrical conductance in HgTe quantum wells delivered the burgeoning field of topological insulators (TIs) its first experimental confirmation. Subsequently, many three-dimensional TIs have been identified among narrow-band-gap semiconductors with strong spin-orbit coupling (SOC), but to date HgTe remains the only known two-dimensional system in this class. Despite much effort, difficulty fabricating HgTe quantum wells and the cryogenic temperatures required to realize the TI phase have hampered their widespread use. In this talk I will discuss a recent proposal for generating a robust TI state in a more readily available two-dimensional system — graphene. Specifically, I will describe how endowing graphene with a small concentration of indium or thallium adatoms can induce a TI phase with a substantial band-gap (which can even approach room temperature for thallium coverage as low as 6%). Engineering such a robust topological phase in graphene could pave the way for a new generation of devices for spintronics, ultra-low-dissipation electronics, and decoherence-free quantum information processing.