Topological crystalline insulator nanomembrane with strain-tunable band gap  

作　　者：Xiaofeng Qian Liang Fu Ju Li 

机构地区：[1]Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA [2]Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

出　　处：《Nano Research》2015年第3期967-979,共13页纳米研究（英文版）

摘　　要：The ability to fine-tune band gap and band inversion in topological materials is highly desirable for the development of novel functional devices. Here we propose that the electronic properties of free-standing nanomernbranes of the topological crystalline insulators （TCI） SnTe and Pb1-xSnx（Se,Te） are highly tunable by engineering elastic strain and membrane thickness, resulting in tunable band gap and giant piezoconductivity. Membrane thickness governs the hybridization of topological electronic states on opposite surfaces, while elastic strain can further modulate the hybridization strength by controlling the penetration length of surface states. We propose a frequency-resolved infrared photodetector using force-concentration induced inhomogeneous elastic strain in TCI nanomembranes with spatially varying width. The predicted tunable band gap accompanied by strong spin-textured electronic states will open new avenues for fabricating piezoresistive devices, infrared detectors and energy-efficient electronic and spintronic devices based on TCI nanomembrane.在拓扑的材料调整乐队差距和乐队倒置的能力为新奇功能的设备的发展是高度合乎需要的。这里，我们建议拓扑的水晶的绝缘体( TCI )的自立的 nanomembranes 的电子性质 SnTe 和 Pb <潜水艇class=“ a-plus-plus ”> 1x </sub > Sn <潜水艇class=“ a-plus-plus ”> x </sub>(Se,Te)由设计有弹性的紧张和膜厚度是高度悦耳的，导致悦耳的乐队差距和巨大的 piezoconductivity 。膜厚度在相反的表面上管理拓扑的电子状态的杂交，当有弹性的紧张能进一步由控制表面状态的穿入长度调制杂交力量时。我们建议用力量集中的一个解决频率的红外线的光电探测器与空间地改变宽度在 TCI nanomembranes 导致了不同类的有弹性的紧张。由强壮的纺纱粗糙的电子状态伴随的预言的悦耳的乐队差距将为制作 piezoresistive 设备打开新大街，红外线的察觉者并且精力有效电子并且 spintronic 设备基于 TCI nanomembrane。

关 键 词：elastic strain engineering pseudoheterostructure infrared photodetector METAL-INSULATORTRANSITION DFT calculations 

分 类 号：O734[理学—晶体学] TB383[一般工业技术—材料科学与工程]