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arXiv 1009.0709cond-mat.mtrl-sci
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LaAlO3-SrTiO3界面电子系统的金属-绝缘体转变

Metal-Insulator Transition of the LaAlO3-SrTiO3 Interface Electron System

Y. C. Liao, T. Kopp, C. Richter, A. Rosch, J. Mannhart

摘要:

本文报道了LaAlO_3-SrTiO_3界面电子系统中的金属-绝缘体转变,其载流子密度由栅极电场调节。当临界载流子密度n_c在0.5-1.5 × 10 ~(13)/cm ~ 2范围内时,形成场效应器件漏源沟道的LaAlO_3-SrTiO_3界面为非欧姆界面。在零沟道偏置下的差分电阻在载流子密度的2%变化内发散。在n_c以上,欧姆沟道的电导率具有类似金属的温度依赖性,而在n_c以下,电导率仅在阈值电场以上才开始。对于一定厚度的LaAlO_3层,其电导率服从σ_0 ~(n-n_c)/n_c特性。发现金属-绝缘体转变与半导体2D系统的金属-绝缘体转变不同。

英文摘要:

We report on a metal-insulator transition in the LaAlO3-SrTiO3 interface electron system, of which the carrier density is tuned by an electric gate field. Below a critical carrier density n_c ranging from 0.5-1.5 * 10^13/cm^2, LaAlO3-SrTiO3 interfaces, forming drain-source channels in field-effect devices are non-ohmic. The differential resistance at zero channel bias diverges within a 2% variation of the carrier density. Above n_c, the conductivity of the ohmic channels has a metal-like temperature dependence, while below n_c conductivity sets in only above a threshold electric field. For a given thickness of the LaAlO3 layer, the conductivity follows a sigma_0 ~(n - n_c)/n_c characteristic. The metal-insulator transition is found to be distinct from that of the semiconductor 2D systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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