Flow diagram of the metal-insulator transition in two dimensions
Flow diagram of the metal-insulator transition in two dimensions
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DOI：
10.1038/nphys685
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发表时间：
2007-10-01
期刊：
影响因子：
19.6
通讯作者：
Klapwijk, T. M.
中科院分区：
文献类型：
--
作者：
Anissimova, S.;Kravchenko, S. V.;Klapwijk, T. M.
二维电子系统中金属-绝缘体转变(MIT)的发现(1)挑战了无序电子物理学中最有影响力的猜想之一(2)的准确性，该猜想声称，在二维中，没有真正的金属行为；无论无序多么弱，电子都会被捕获，无法传导电流。然而，这一理论没有考虑到电子之间的相互作用。在这里，我们通过同时测量电阻率和磁导来研究麻省理工学院附近电子-电子相互作用和无序之间的相互作用。我们发现，当MIT穿过时，阻力和相互作用幅度都呈现出扇形扩展。根据这些数据，我们构建了麻省理工学院的阻力-相互作用流程图，清楚地揭示了双参数标度理论所预测的量子临界点(3)。重整化群理论(4)在没有任何拟合参数的情况下，精确地描述了该图的金属边。特别是，当相互作用幅度达到伽马(2)时，电阻的金属温度依赖关系开始出现--这一值与理论(4)的预测值非常一致。
The discovery of the metal-insulator transition (MIT) in two-dimensional electron systems(1) challenged the veracity of one of the most influential conjectures(2) in the physics of disordered electrons, which states that 'in two dimensions, there is no true metallic behaviour'; no matter how weak the disorder, electrons would be trapped and unable to conduct a current. However, that theory did not account for interactions between the electrons. Here, we investigate the interplay between the electron-electron interactions and disorder near the MIT using simultaneous measurements of electrical resistivity and magnetoconductance. We show that both the resistance and interaction amplitude exhibit a fan-like spread as the MIT is crossed. From these data, we construct a resistance-interaction flow diagram of the MIT that clearly reveals a quantum critical point, as predicted by the two-parameter scaling theory(3). The metallic side of this diagram is accurately described by the renormalization-group theory(4) without any fitting parameters. In particular, the metallic temperature dependence of the resistance sets in when the interaction amplitude reaches gamma(2) approximate to 0.45 - a value in remarkable agreement with the one predicted by theory(4).