Princeton University

School of Engineering & Applied Science

Magneto-transport Study of Quantum Phases in Wide GaAs Quantum Wells

Yang Liu
Engineering Quadrangle B327
Thursday, February 13, 2014 - 2:00pm to 3:30pm

At low temperature and subjected to a high magnetic field, a low-disorder two-dimensional electron system (2DES) displays a myriad of novel collective many-body quantum phases, arising from the dominance of the Coulomb interaction energy over the kinetic energy and the disorder potential. My research is studying the 2DES confined to modulation doped GaAs/AlGaAs quantum wells, which are grown by molecular beam epitaxy and have extremely high mobility. By carefully applying front- and back-gate voltages, we can fine tune the electron density and charge distribution symmetries. The ground state of the 2DES exhibit rich transitions between different quantum phases, e. g. the fractional quantum Hall effect, compressible Fermi sea, stripe phase and Wigner crystals. The evolutions of all these states provide us with a tool for studying how the 2DES depends on the details of electron-electron interaction. This helps us understand how interaction plays a role in the properties of matters, and learn the fundamental characteristics of matters