Fermi level tuning in Sn1-xPbxTe/Pb heterostructure via changing interface roughness

IF 6.4 1区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Science China Physics, Mechanics & Astronomy Pub Date : 2024-07-16 DOI:10.1007/s11433-024-2383-6

Tengteng Liu, Zhaoxia Yi, Bangjin Xie, Weiyan Zheng, Dandan Guan, Shiyong Wang, Hao Zheng, Canhua Liu, Hao Yang, Yaoyi Li, Jinfeng Jia

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引用次数: 0

Abstract

Superconducting SnTe-type topological crystalline insulators (TCIs) are predicted to host multiple Majorana zero modes (MZMs) which can coexist in a single vortex. Fermi level (FL) close to the Dirac points of topological surface states is helpful for detecting MZMs. However, the TCI SnTe is a heavily p-type semiconductor which is very difficult to modify to n-type via doping or alloying. In this work, we fabricate the atomically flat Sn_1-xPb_xTe/Pb heterostructure by molecular beam epitaxy, and make the p-type Sn_1-xPb_xTe become n-type through changing the interface roughness. Using scanning tunnelling microscope, we find the Dirac points of Sn_1-xPb_xTe/Pb heterostructure are always above the FL due to the Fermi level pinning (FLP) induced by topological surface states at atomically flat interface. After increasing the interface roughness, the FLP effect is suppressed and then the Dirac points of p-type Sn_1-xPb_xTe can be tuned very close to or even below the FL. Our work provides a new method for tuning the FL of SnTe-type TCI which has potential application in novel topological superconductor device.

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通过改变界面粗糙度调谐 Sn1-xPbxTe/Pb 异质结构中的费米级

据预测，超导锡碲型拓扑晶体绝缘体（TCIs）可容纳多个马约拉纳零模（MZMs），这些零模可共存于单个涡旋中。接近拓扑表面态狄拉克点的费米级（FL）有助于探测 MZMs。然而，TCI SnTe 是一种严重的 p 型半导体，很难通过掺杂或合金化将其转变为 n 型。在这项工作中，我们通过分子束外延技术制备了原子平坦的 Sn1-xPbxTe/Pb 异质结构，并通过改变界面粗糙度使 p 型 Sn1-xPbxTe 变为 n 型。利用扫描隧穿显微镜，我们发现 Sn1-xPbxTe/Pb 异质结构的狄拉克点总是在 FL 的上方，这是由于原子平坦界面上的拓扑表面态诱导了费米级针销（FLP）。增加界面粗糙度后，FLP 效应被抑制，p 型 Sn1-xPbxTe 的狄拉克点就可以调谐到非常接近甚至低于 FL。我们的研究为调整 SnTe 型 TCI 的 FL 提供了一种新方法，有望应用于新型拓扑超导体器件。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Science China Physics, Mechanics & Astronomy PHYSICS, MULTIDISCIPLINARY-

CiteScore

10.30

自引率

6.20%

发文量

4047

审稿时长

3 months

期刊介绍： Science China Physics, Mechanics & Astronomy, an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China, and published by Science China Press, is committed to publishing high-quality, original results in both basic and applied research. Science China Physics, Mechanics & Astronomy, is published in both print and electronic forms. It is indexed by Science Citation Index. Categories of articles: Reviews summarize representative results and achievements in a particular topic or an area, comment on the current state of research, and advise on the research directions. The author’s own opinion and related discussion is requested. Research papers report on important original results in all areas of physics, mechanics and astronomy. Brief reports present short reports in a timely manner of the latest important results.