Thermodynamical study of the electron-hole system in ultrathin films of pure bismuth in quantizing magnetic fields

The chemical potential, carrier density, electronic specific heat, magnetization, and magnetic susceptibility of the electron-hole system in an ultrathin film of pure bismuth have been numerically evaluated as functions of the temperature and the intensity of a transversely applied magnetic field. The film, being normal to the trigonal axis of the crystalline structure, is assumed to be sufficiently thin so that the extreme quantum size effect can be realized and the electrons and holes perform approximately two-dimensional motions. The unique energy band structure of semimetal bismuth gives rise to many peculiar results, including the temperature dependence of the aforementioned thermodynamical quantities and the de Haas–van Alphen type oscillations of the magnetization. The results are significantly deviated from those of a two-dimensional free-electron Fermi gas.