Strong quantum confinement and topological phases in two-dimensional crystals

Date

Jan 28, 2016

Time

1:00 PM - 2:00 PM

Speaker

Prof. Thomas Heine

Affiliation

Universität Leipzig, Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Linnéstr. 2, 04103 Leipzig, Germany

Series

TUD nanoSeminar

Language

en

Main Topic

Materialien

Other Topics

Materialien

Host

G. Cuniberti

Description

Since the rise of graphene and other two-dimensional crystals scientists understood that physics in two dimensions is different. There is a large manifold of 2D crystals, many of them showing strong quantum confinement, spin-orbit effects and response to external fields. I will present noble metal chalcogenides that exhibit particularly strong quantum confinement. In particular PdS 2 shows a semiconducting phase as monolayer, but a metallic one as bilayer. This property can be exploited in designing a single-metal transistor with negligible contact resistance. Two-dimensional topological insulators (2DTI), also commonly referred to as quantum spin hall states, have been proposed in 2007, when a HgTe layer was embedded in a CdTe matrix. For layer thickness less than 6.3 nm, the system showed the properties of a 2DTI. Unfortunately, known 2DTI systems have very small bulk band gaps that restricts their application to very low temperature. We are exploring 2D materials that show all characteristics of 2DTI, but have at the same time a large bulk band gap. Here, we concentrate on allotropes of Group 6 transition metal dichalcogenides 6 and on buckled saturated Group 13 and Group 14 phases.

Last modified: Apr 11, 2016, 9:48:48 AM