Electronic ground state of inversion layers in many-valley semiconductors

Abstract

We present a self-consistent many-body calculation of the possible ground states in the inversion layers of many-valley semiconductors (as typified by Si) in the metal-oxide-semiconductor configuration. A complex phase diagram results when the various electronic interactions are regarded as free parameters; for experimentally reasonable values, a charge-density wave is the ground state at the Si(111)-Si${\mathrm{O}}_2$ interface with the experimentally observed valley degeneracy and cyclotron mass. At the Si(100)-Si${\mathrm{O}}_2$ interface, the paramagnetic state remains stable over the experimentally accessible region of the phase diagram. Applications to other systems are briefly mentioned and experimental tests of the theory are suggested.