Sandow B, Gloos K, Rentzsch R, Ionov A N, Schirmacher W
Institut für Experimentalphysik, Freie Universität Berlin, Germany.
Phys Rev Lett. 2001 Feb 26;86(9):1845-8. doi: 10.1103/PhysRevLett.86.1845.
We have investigated the effect of the long-range Coulomb interaction on the one-particle excitation spectrum of n-type germanium, using tunneling spectroscopy on mechanically controllable break junctions. At low temperatures, the tunnel conductance shows a minimum at zero bias voltage due to the Coulomb gap. Above 1 K, the gap is filled by thermal excitations. This behavior is reflected in the variable-range hopping resistivity measured on the same samples: up to a few degrees Kelvin the Efros-Shklovskii lnR infinity T(-1/2) law is obeyed, whereas at higher temperatures deviations from this law occur. The type of crossover differs from that considered previously in the literature.
我们利用机械可控断裂结的隧穿光谱，研究了长程库仑相互作用对n型锗单粒子激发光谱的影响。在低温下，由于库仑能隙，隧道电导在零偏置电压处出现最小值。高于1 K时，能隙被热激发填充。这种行为反映在对相同样品测量的变程跳跃电阻率中：在高达几开尔文的温度范围内，遵循埃弗罗斯-什克洛夫斯基lnR∝T^(-1/2)定律，而在较高温度下会出现偏离该定律的情况。这种转变类型与文献中先前考虑的不同。
