Nematic quantum fluids with wavefunctions that break the underlying crystalline symmetry can form in interacting electronic systems. We examine the quantum Hall states that arise in high magnetic fields from multiple anisotropic hole pockets on the Bi(111) surface. Spectroscopy performed with a scanning tunneling microscope shows that a combination of single-particle effects and many-body Coulomb interactions lift the Landau level (LL) degeneracy. We image the resulting anisotropic LL wavefunctions and find that they have a different orientation for each broken-symmetry state, which provides a direct spatial signature of a nematic electronic phase.
"Observation of a nematic quantum Hall liquid on the surface of bismuth," Benjamin E. Feldman, Mallika T. Randeria, András Gyenis, Fengcheng Wu, Huiwen Ji, R. J. Cava, Allan H. MacDonald, Ali Yazdani, Science 354, 6310 (2016). (Article)
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