Transport properties of two-dimensional hole gas in a Ge1-xSix/Ge/Ge1-xSix quantum well in the vicinity of metal-insulator transition

摘要

Observation of a low-temperature transition from metallic (partial derivative p/partial derivative T > 0) to insulator (partial derivative p/partial derivative T < 0) behavior of resisitivity p(T) induced by a perpendicular magnetic field B is reported for a two-dimensional (2D) hole system confined within Ge layers of a p-Ge1-xSix/Ge/Ge1-xSix heterostructure. The essential feature of this system is that it is described by the Luttinger Hamilton with the g-factor highly anisotropic for orientations of magnetic field perpendicular and parallel to the 2D plane (g(perpendicular to) g(parallel to)). The positive magnetoresistance revealed scales as a function of B/T We attribute this finding to suppression of the triplet channel of electron-electron (hole-hole) interaction due to Zeeman splitting in the hole spectrum.