Princeton University

School of Engineering & Applied Science

Interacting Bilayer Electron System

Hao Deng
Mansour Shayegan
B-327, E-Quad
Tuesday, October 9, 2018 - 1:00pm to 2:00pm

The interacting bilayer electron system provides a versatile, extended platform to study electron-electron interaction beyond single layer. At low temperatures and high magnetic fields, by setting each layer at a different density, the bilayer electron system hosts different electronic phases in each layer; moreover, we can study the role of interaction between these phases when the two layers are closely spaced.

In this talk, I would like to present my research on the interaction between magnetic-field-induced Wigner crystal (WC) and composite fermion (CF) liquid implemented in the bilayer electron system. We tune one (minority) layer to a very low density so that it is in the WC regime, while the other, high-density (majority) layer hosts a sea of CFs near half Landau level filling. The transport measurements of the majority layer exhibit commensurability oscillations in the magnetoresistance, induced by the periodic potential of WC electrons in the minority layer, and provide a unique, direct glimpse at the symmetry of the WC, its lattice constant, and melting. Furthermore, by scrutinizing the details of the interlayer charge transfer as a function of magnetic field, we are able to measure the critical filling factor below which WC forms in the minority layer when the majority layer is present in close proximity. The data reveal that the WC forms at a significantly smaller filling compared to the one in single-layer two-dimensional electron systems. The measured critical filling factor exhibits a strong dependence on the interlayer distance, reflecting the interaction and screening from the adjacent, high-density layer.