报告简介

Topological insulators (TIs) are quantum materials that are insulating in the bulk and conducting on the surface. Strong spin-orbit coupling creates a band inversion that is responsible for the appearance of spin-polarised conducting edge states which resemble the edge states of the quantum Hall effect. However, topological surface states can exist without a magnetic field and at room temperature. This makes them interesting candidates for device applications.

A big challenge in TI device development is the fact that the bulk is not as insulating as it should be due to intrinsic n-type behaviour for example in Bi2Se3 and Bi2Te3, which are two of the earliest TI materials. This can be tackled by reducing the volume of the crystals to nanostructure size by the synthesis of nanowires.

However, TI materials grow different from most quasi-one dimensional crystals in vapour transport experiments. This talk explores the growth of Bi2Se3 and Bi2Te3 nanostructures starting from a qualitative analysis of the growth mechanism. We then combine the nanostructure growth with chemical doping that also tackles intrinsic n-type behaviour. This leads to the discovery of the new TI orthorhombic Sb:Bi2Se3 and a superconductor/TI heterostructure Sn patterned Bi2Te3.

报告人简介

Piet is a 3rd year PhD student at the University of Oxford in the Thin Film Quantum Materials group. He has been working on nanostructures for six year. In 2013, Piet graduated from Freie Universität Berlin. His Master studies included research visits at Tsinghua University, at SINANO in Suzhou, and a one-year project at Oxford.

时间：2016年06月20日（周一）15:30

地点：物理馆220会议室

物理科学与技术学院

中英联合材料研究所