Reentrant Insulator-Metal-Insulator Transition at B 5 0 in a Two-Dimensional Hole Gas
Reentrant Insulator-Metal-Insulator Transition at B 5 0 in a Two-Dimensional Hole Gas
复制标题
二维空穴气体中 B 5 0 处的重入绝缘体-金属-绝缘体转变
DOI：
10.1103/physrevlett.82.1542
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发表时间：
1998
影响因子：
8.6
通讯作者：
D. Ritchie
中科院分区：
文献类型：
--
作者：
A. Hamilton;M. Simmons;M. Pepper;E. Linfield;P. D. Rose;D. Ritchie
我们报道了在温度低至30mK的GaAs中二维（2D）空穴气体中在B=0处观察到的重新进入绝缘体-金属-绝缘体转变。在最低载流子密度下，空穴是强局域化的。随着载流子密度的增加，形成金属相，在\sigma = ~5e^2/h时发生明显转变。进一步增加密度会削弱金属行为，最终导致第二绝缘态的形成，速率为\sigma > ~50e^2/h。在高载流子密度的极限下，其中k_F。l大而r_s小，我们因此恢复了先前在二维弱相互作用系统中显示金属态缺失的结果。
We report the observation of a re-entrant insulator--metal--insulator transition at B=0 in a two dimensional (2D) hole gas in GaAs at temperatures down to 30mK. At the lowest carrier densities the holes are strongly localised. As the carrier density is increased a metallic phase forms, with a clear transition at \sigma = ~5e^2/h. Further increasing the density weakens the metallic behaviour, and eventually leads to the formation of a second insulating state for \sigma > ~50e^2/h. In the limit of high carrier densities, where k_F.l is large and r_s is small, we thus recover the results of previous work on weakly interacting systems showing the absence of a metallic state in 2D.