April 1, 2018 at 7:30 pm

CMSS Colloquium | Enhanced Functionalities from Designed vdW Interfaces, April 19

The Condensed Matter & Surface Sciences Colloquium Series presents Lian Li of West Virginia University on “Enhanced Functionalities from Designed vdW Interfaces”, on Thursday, April 19, at 4:10 p.m. in Walter 245.

Lian Li

Lian Li

Abstract: In his Nobel lecture, Kroemer famously opened with the claim “Often, it may be said that the interface is the device”. Nowhere is this more true than in two-dimensional (2D) materials, whose properties can only be meaningfully discussed when their interfaces with the substrates are clearly defined. The band gap of graphene provides an apt example. It is on the order of μeV while freestanding, but can reach tens of meV on h-BN. Perhaps the most surprising example of substrate dependence in a 2D material is the recent discovery of an order-of-magnitude increase in superconducting transition temperature (TC) when a single layer of FeSe is grown on SrTiO3(001) substrate.

In this talk, I will highlight our work on the giant spin-orbit splitting of the graphene Dirac states of up to 80 meV in graphene/topological insulator Bi2Se3 van der Waals (vdw) heterostructure due to indirect interfacial bonding, and the control of TC in single layer FeSe/SrTiO3 by engineering interface reconstruction. Our findings reveal unique challenges for the epitaxial growth of these 2D materials, as well as opportunities for tailoring their physical and electronic properties at the interface.

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