Real-space imaging of a nematic quantum liquid

Speaker: Ben Feldman, Princeton University

When: February 6, 2017 (Mon), 02:30PM to 03:30PM (add to my calendar)
Location: SCI 328

This event is part of the Biophysics/Condensed Matter Seminar Series.

The wave functions of electronic states in solids typically respect the symmetries of the host material. However, interactions among electrons can give rise to a variety of exotic correlated phases characterized by broken symmetry. An intriguing example is the formation of electron fluids with wave functions that spontaneously break the symmetry of the underlying crystal lattice. These phases are quantum analogues of classical liquid crystals and have been studied in recent years across disparate platforms ranging from high-temperature superconductors to two-dimensional electron systems. In this talk, I will describe scanning tunneling microscope measurements that allow us to visualize such a quantum liquid in real space. We examine the quantum Hall states that arise at high magnetic field from anisotropic Fermi pockets on the surface of bismuth. Our measurements reveal that a combination of strain and exchange interactions lift the Landau level degeneracy and produce valley-polarized states. We image the resulting anisotropic wave functions and find that they have a different orientation for each broken-symmetry state, providing a direct spatial signature of a nematic electronic phase.