Magnetic field driven metal-insulator phase transition in planar systems

摘要

A theory of the magnetic field driven (semi-)metal-insulator phase transitionis developed for planar systems with a low density of carriers and a linear(i.e., relativistic like) dispersion relation for low energy quasiparticles.The general structure of the phase diagram of the theory with respect to thecoupling constant, the chemical potential and temperature is derived in twocases, with and without an external magnetic field. The conductivity andresistivity as functions of temperature and magnetic field are studied indetail. An exact relation for the value of the "offset" magnetic field $B_c$,determining the threshold for the realization of the phase transition at zerotemperature, is established. The theory is applied to the description of arecently observed phase transition induced by a magnetic field in highlyoriented pyrolytic graphite.