选区外延生长的PbTe-超导杂化纳米线:一个可能实现拓扑量子计算的新体系

Selective-area-epitaxied PbTe-superconductor hybrid nanowires:A new candidate system to realize topological quantum computing

半导体-超导体杂化纳米线是用于研究马约拉纳零能模和拓扑量子计算的主要平台之一,而基于Ⅲ-Ⅴ族半导体InAs和InSb的纳米线则是当前此方向研究的主流材料体系.尽管经过多年制备技术的改进和优化,样品中过多的缺陷和杂质仍是阻碍此方向进一步发展的核心问题.近年来,一个新的马约拉纳纳米线候选体系——Ⅳ-Ⅵ族半导体PbTe-超导杂化纳米线吸引了很大关注并获得了快速的研究进展.PbTe的介电常数巨大,且具有晶格匹配的衬底,这些优势使其有潜力突破纳米线样品质量提升的瓶颈,成为马约拉纳零能模的研究和拓扑量子计算实现的理想平台.本文将简单介绍最近几年在PbTe纳米线和PbTe-超导杂化纳米线器件的选区分子束外延生长、输运性质研究方面取得的重要进展,并对这种新的马约拉纳纳米线候选体系的优势、问题及基于其实现拓扑量子计算的前景进行讨论.

Semiconductor-superconductor hybrid nanowire is one of the major platforms for realizing Majorana zero modes(MZMs)and topological quantum computing(TQC),and the III-V InAs and InSb-based nanowires are the most-studied materials in this approach.Despite years of efforts to improve and optimize materials,too many defects and impurities in the nanowire samples remain the central problem hindering the research progress in this direction.In recent years,a new candidate Majorana nanowire system-IV-VI semiconductor PbTe-superconductor hybrid nanowire-has attracted much attention and witnessed rapid research progress.The unique advantages of PbTe-based nanowires,such as the large dielectric constant and the presence of a lattice-matched substrate,give them great potential in solving the bottleneck problem of sample defects and impurities,making them an ideal platform for studying MZMs and TQC.In this paper,we briefly introduce the recent research progress of selective area growth and transport characterization of in-plane PbTe nanowires and PbTe-superconductor hybrid nanowires.We also discuss the advantages and problems of the new candidate Majorana nanowire system as well as the prospect of realizing TQC based on it.