Das Sarma S, Lilly M P, Hwang E H, Pfeiffer L N, West K W, Reno J L
Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
Phys Rev Lett. 2005 Apr 8;94(13):136401. doi: 10.1103/PhysRevLett.94.136401. Epub 2005 Apr 5.
By carefully analyzing the low temperature density dependence of 2D conductivity in undoped high-mobility n-GaAs heterostructures, we conclude that the 2D metal-insulator transition in this 2D electron system is a density inhomogeneity driven percolation transition due to the breakdown of screening in the random charged impurity disorder background. In particular, our measured conductivity exponent of approximately 1.4 approaches the 2D percolation exponent value of 4/3 at low temperatures and our experimental data are inconsistent with there being a zero-temperature quantum critical point in our system.
通过仔细分析未掺杂的高迁移率n型砷化镓异质结构中二维电导率的低温密度依赖性，我们得出结论：在这个二维电子系统中，二维金属-绝缘体转变是由于随机带电杂质无序背景下屏蔽的破坏而导致的密度不均匀性驱动的渗流转变。特别是，我们测得的电导率指数在低温下约为1.4，接近二维渗流指数4/3的值，并且我们的实验数据与我们的系统中存在零温度量子临界点不一致。
