Allison G, Galaktionov E A, Savchenko A K, Safonov S S, Fogler M M, Simmons M Y, Ritchie D A
School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom.
Phys Rev Lett. 2006 Jun 2;96(21):216407. doi: 10.1103/PhysRevLett.96.216407.
We perform combined resistivity and compressibility studies of two-dimensional hole and electron systems which show the apparent metal-insulator transition--a crossover in the sign of deltaR/deltaT with changing density. No thermodynamic anomalies have been detected in the crossover region. Instead, despite a tenfold difference in r(s), the compressibility of both electrons and holes is well described by the theory of nonlinear screening of the random potential. We show that the resistivity exhibits a scaling behavior near the percolation threshold found from analysis of the compressibility. Notably, the percolation transition occurs at a much lower density than the crossover.
我们对二维空穴和电子系统进行了电阻率和压缩性的联合研究，这些系统显示出明显的金属-绝缘体转变——随着密度变化，ΔR/ΔT的符号发生转变。在转变区域未检测到热力学异常。相反，尽管r(s)相差十倍，但电子和空穴的压缩性都能很好地用随机势的非线性屏蔽理论来描述。我们表明，电阻率在通过压缩性分析得出的渗流阈值附近呈现标度行为。值得注意的是，渗流转变发生时的密度远低于转变时的密度。
