Localization and phase transition do not take place in the extreme quantum limit
Clarification of Landau spectrum and twin boundaries
Under the leadership of FUSEYA Yuki , Associate Professor, Faculty of Informatics and Engineering, The University of Electro-Communications (then Assistant professor, Graduate School of Engineering Science, Osaka University) and Kamran Behnia , Professor, Laboratoire de Physique et d’Etude des materiaux Ecole Superieure de Physique et de Chimie Industrielles Paris, France, a group of researchers have clarified Landau spectrum and twin boundaries of bismuth in the extreme quantum limit.
The Landau spectrum of bismuth is complex and includes many angle-dependent lines in the extreme quantum limit. The adequacy of single-particle theory to describe this spectrum in detail has been an open issue. Here, we present a study of angle-resolved Nernst effect in bismuth, which maps the angle-resolved Landau spectrum for the entire solid angle up to 28 T. The experimental map is in good agreement with the results of a theoretical model with parabolic dispersion for holes and an extended Dirac Hamiltonian for electrons.
The angular dependence of additional lines in the Landau spectrum allows to uncover the mystery of their origin. They correspond to the lines expected for the hole Landau levels in a secondary crystal tilted by 108 degrees, the angle between twinned crystals in bismuth.
According to our results, the electron reservoirs of the two identical tilted crystals have different chemical potentials and carriers across the twin boundary have different concentrations. An exceptional feature of this junction is that it separates two electron-hole compensated reservoirs. The link between this edge singularity and the states wrapping a three-dimensional electron gas in the quantum limit emerges as an outstanding open question.
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To read the full research report on this important , please read the full research report entitled " Landau spectrum and twin boundaries of bismuth in the extreme quantum limit " at this page at the PNAS website.
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