Quantum Magnetic Oscillations of the Surface Tension at a Metal-Insulator Interface

Anymetal-insulator transition (MI transition) in a crystallinematerialmust be a transition from a situation in which electronic bands overlap to a situation when they do not (Mott, Metal-insulator, 2nd edn. Taylor@ Francis, London, 1990). For this case the self-consistent equations for the two-band conductor are formulated (cf. Dubovskii, JETP Lett. 99(1): 22-26, 2014). The description of the MI phase transition is based on two order parameters. The first one is thematerial density distribution at the MI boundary rho((r) over right arrow). The second one is a four-component complex vector in spin space gamma((r) over right arrow). The value gamma((r) over right arrow) determines the electron density in the metallic or semimetallic phase in the presence of an external magnetic field. Two different components of the vector describe possible spin states of electrons and holes inserted in the external magnetic field. The solution gives a singular behavior of the surface tension at the MI interface in the vicinity of the MI phase transition. At low temperature quantum oscillations of the surface tension in the magnetic field take place.