Abstract
We argue that at finite carrier density and large displacement fields, bilayer graphene is prone to and Pomeranchuk Fermi-surface instabilities. The broken symmetries are driven by nonlocal exchange interactions which favor momentum-space condensation. We find that electron-electron interactions lead first to spontaneous valley polarization, which breaks time-reversal invariance and is associated with spontaneous orbital magnetism, and then under some circumstances to a nematic phase with reduced rotational symmetry. When present, nematic order is signaled by reduced symmetry in the dependence of optical absorption on light polarization.
- Received 2 March 2015
DOI:https://doi.org/10.1103/PhysRevB.91.155423
©2015 American Physical Society