Physics Library, Room 223A, Physics Building
The MU Physics & Astronomy Department’s Condensed Matter - Biological Physics - Electrical & Computer Engineering seminar series presents, "Novel Emergent Inhomogeneous Phases in Electron-hole Graphene Bilayers," by Mohammad Zarenia, MU Visiting Scholar, Wednesday, April 4, 4:00 p.m., Physics 223A, Library. Refreshments will be served beginning at 3:30 p.m.
Zarenia writes, "I propose two strongly coupled two-dimensional (2D) bilayers of graphene, one bilayer containing electrons and the other holes separated by hexagonal Boron Nitride dielectric, as an experimentally accessible system to observe novel emergent many-body phases. This system is currently attracting a lot of experimental interest. I will first demonstrate that coupled electron-hole bilayer graphene as well as coupled few-layer graphene sheets with carrier densities in a range accessible to experiments, can access the regime of strong pairing necessary for superfluidity. For the coupled bilayer graphene system, we find two new inhomogeneous ground states, a one-dimensional Charge Density Wave (1D-CDW) phase, i.e. density modulations in one planar direction, and a coupled electron-hole Wigner crystal (c-WC) in association with the superfluid phase. To account for the strong inter-layer correlation energy accurately, I introduce a new approach which is based on a random phase approximation at high densities and an interpolation between the weakly- and strongly-interacting regimes. The approach gives excellent agreement with available Quantum Monte Carlo calculations for single layer two-dimensional-electron-gas systems. In addition to a fundamental interest in observing these new exotic inhomogeneous phases, demonstration of the existence of inhomogeneous phases in conjunction with a superfluid phase within such a crystallographically simple system, should add to our insight into the role of striped phases in High-Temperature superconductors."