Structure and phase transition of a uniaxially incommensurate In monolayer on Si(111)
Structure and phase transition of a uniaxially incommensurate In monolayer on Si(111)
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Si(111)上单轴不相称In单层的结构和相变
DOI：
10.1103/physrevb.100.115428
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发表时间：
2019
影响因子：
3.7
通讯作者：
Aruga Tetsuya
中科院分区：
文献类型：
--
作者：
Terakawa Shigemi;Hatta Shinichiro;Okuyama Hiroshi;Aruga Tetsuya
本文研究了In在Si（111）上的致密金属单层膜的原子结构和相变。虽然单层相以前被认为具有（λ 7× λ 3）周期性，但低能电子衍射和扫描隧道显微镜观察显示，该相具有不公度结构，In覆盖层从（λ 7× λ 3）单轴收缩2%。通过第一性原理计算，发现单轴收缩结构比公度（107 × 103）结构更稳定.在250-210 K温度范围内，我们还观察到了（107 × 107）相的相变。角分辨光电子能谱和宏观四点探针电导率测量表明，过渡引起的金属表面状态的消失和急剧下降的片电导率，分别。这些结果表明电子金属-绝缘体转变。
We have studied the atomic structure and phase transition of a dense metallic monolayer of In on Si (111). Although the monolayer phase was previously considered to have a (√ 7×√ 3) periodicity, low-energy electron diffraction and scanning tunneling microscopy observations have revealed that the phase has an incommensurate structure with the In overlayer uniaxially contracted by 2% from (√ 7×√ 3). The uniaxially contracted structure was found to be more stable than the commensurate (√ 7×√ 3) structure by first-principles calculations. We also observed a phase transition to a (√ 7×√ 7) phase at 250–210 K upon cooling. Angle-resolved photoelectron spectroscopy and macroscopic four-point-probe conductivity measurements demonstrated that the transition induces the disappearance of metallic surface states and a sharp drop in sheet conductivity, respectively. These results indicate an electronic metal-insulator transition.