Conduction electrons in an impurity band: NMR in Ge:As

摘要: The 73Ge spin-lattice relaxation time T1 has been studied at 4.2K and below in single-crystal specimens of arsenic-doped germanium (Ge:As), with doping densities spanning the metal-non-metal transition. An increase applied magnetic field is observed for both semiconducting low-density metallic 'impurity-banded' materials, although independent heavily doped samples. behaviour region interpreted here using two models band which conduction electrons move, based on tight-binding rigid-band approaches, results are compared those other workers related Si:P system. Very little support can be adduced from this work dominance correlation as driving mechanism transition Ge:As. indicate that Ge:As occurs when impurity overlaps band.