EXPERIMENTAL-EVIDENCE FOR A COULOMB GAP IN 2 DIMENSIONS

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关键词: HOPPING CONDUCTION;    IMPURITY BAND;   

DOI  :  10.1103/PhysRevB.52.7857

来源: SCIE

【 摘 要 】

We have studied the resistivity of a two-dimensional electron system in silicon in the temperature range 200 mK < T < 7.5 K at zero magnetic field at low electron densities, when the electron system is in the insulating regime. Our results show that at an intermediate temperature range, rho = rho(0) exp [(T-0/T)1/2] for at least four orders of magnitude up to 3 x 10(9) Omega. This behavior is consistent with the existence of a Coulomb gap. Near the metal/insulator transition, the prefactor was found to be p(0) approximate to h/e(2), and resistivity scales with temperature. For very low electron densities n(s), the prefactor diminishes with diminishing n(s). A comparison with the theory shows that a specific set of conditions are necessary to observe the behavior of resistivity consistent with the existence of the Coulomb gap.

【 授权许可】

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