The results of two studies of disordered metals neartheir metal-insulator transition are presented: (i) Adetailed comparison of GexAu1-x and BxCu1-x is carried out inzero magnetic field. GeAu, a high Z material, has been shownto e xh1bit strong spin-orbit effects in a magnetic fieldwhile 8Cu, a low Z material, has been shown to exhibit weakspin-orbit effects. Both materials have similar temperaturedependent de conductivity behavior in zero field andapproximately linear mobility edges; CiilA detailed stud~ ofthe non-linear dc conductivitu of GeAu and Cx - Cu1-xis carriedout for 1.3K< data in the context of an electron gasheating model fields unphysically long electron relaxationtimes. Alternatively, the E-field can limit renormalizationby raising the electron energy above the disorderedpotential. The s~stem then changes from quantum mechanicalscaling to classically diffusive behavior beyond a certainlength scale . The temperature and E-field data can then givethe characteristic lengths and prefactors for the transition.
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Spin-orbit scattering and E-field effects in discordered metals near the metal-insulator transition