Materials design from nonequilibrium steady states: driven graphene as a tunable semiconductor with topological properties

• Published in: Physical review letters Vol. 110; no. 17; p. 176603
• Main Authors: Iadecola, Thomas, Campbell, David, Chamon, Claudio, Hou, Chang-Yu, Jackiw, Roman, Pi, So-Young, Kusminskiy, Silvia Viola
• Format: Journal Article
• Language: English
• Published: United States 25.04.2013
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.110.176603

Controlling the properties of materials by driving them out of equilibrium is an exciting prospect that has only recently begun to be explored. In this Letter we give a striking theoretical example of such materials design: a tunable gap in monolayer graphene is generated by exciting a particular optical phonon. We show that the system reaches a steady state whose transport properties are the same as if the system had a static electronic gap, controllable by the driving amplitude. Moreover, the steady state displays topological phenomena: there are chiral edge currents, which circulate a fractional charge e/2 per rotation cycle, with the frequency set by the optical phonon frequency.