负带隙HgCdTe体材料的磁输运特性研究  

Magnetotransport property of negative band gap HgCdTe bulk material

作　　者：沈丹萍 张晓东 孙艳[2] 康亭亭[2] 戴宁[2] 褚君浩[2] 俞国林[2] 

机构地区：[1]东华大学理学院,上海201620 [2]中国科学院上海技术物理研究所,红外物理国家重点实验室,上海200083

出　　处：《物理学报》2017年第24期211-216,共6页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2016YFA0202201);国家自然科学基金(批准号:11774367)资助的课题~~

摘　　要：通过单晶生长了Cd组分为0.1的p型HgCdTe体材料,并制备了具有倒置型能带序的HgCdTe场效应器件.通过磁输运测试,在负带隙HgCdTe体材料中观察到明显的量子霍尔平台效应和Shubnikov-de Haas(SdH)振荡效应,证明样品具有较好的质量.利用SdH振荡对1/B关系的快速傅里叶变换,得到了样品的零场自旋分裂能约为26.55 meV,证明样品中存在强自旋-轨道耦合作用.进一步分析SdH中的拍频节点估算了样品中的有效g因子约为–11.54.In recent years, spintronic devices have attracted more and more attention because of their good characteristics.The spin-orbit coupling of HgCdTe is one of the most important parts in the study of narrow gap semiconductors.The magneotransport properties of the Hg（0.9）Cd（0.1）Te bulk material with an inverted band structure have been hardly reported so far. The spin-orbit coupling strength of HgCdTe is closely related to the band gap. The strength of the spin-orbit coupling increases with the width of the band gap decreasing. Thus, Hg（0.9）Cd（0.1）Te should have strong spinorbit coupling. Meanwhile it should be one of the most suitable materials to fabricate spintronic devices. The main propose of our experiments is to prove this inference. Inside the sample, Rashba spin-orbit interaction（SOI） strongly influences the spin-splitting due to the lack of structural inversion symmetry. In other words, Rashba SOI is the main part of the zero field spin splitting ？0. The band structure of Hg（1-x）CdxTe can be precisely tuned by changing the composition of Cd which keeps an inverted band order when 0 x 0.165 and returns to the normal case with the Γ8 band lying below the Γ6 band（or equivalently a positive band gap） when x 0.165. In this paper, the p-type HgCdTe bulk material with Cd component of 0.1 is grown by single crystal. Anodic oxidation is used to induce an inversion layer on the HgCdTe bulk, and indium is used to facilitate Ohmic contacts. The magnetoresistance is measured in the van der Pauw configuration, and the magnetic field is applied perpendicularly to the film. All measurements are carried out in an Oxford Instruments He cryogenic system. At 1.5 K and zero gate voltage, the carrier density n is 1.3 × 10^（16）m^（-2）. Clear Shubnikov-de Haas（SdH） oscillation in ρxxand quantum Hall plateaus of R（xy） are observed in the Hg（0.9）Cd（0.1）Te bulk material with an inverted band structure is investigated in magnetotransport experiment. This indicates that our samp

关 键 词：HGCDTE Shubnikov-de Haas振荡 零场自旋分裂能 

分 类 号：O471.1[理学—半导体物理] O482.5[理学—物理]