Publication Date

5-19-2021

Department

Ames Laboratory; Physics and Astronomy

Campus Units

Physics and Astronomy, Ames Laboratory

OSTI ID+

1784516

Report Number

IS-J 10475

DOI

10.1021/acsphotonics.1c00216

Journal Title

ACS Photonics

Abstract

Emerging topological semimetals offer promise of realizing topological electronics enabled by terahertz (THz) current persistent against impurity scattering. Yet most fundamental issues remain on how to image nanoscale conductivity inhomogeneity. Here we show noninvasive and contactless conductivity mapping at THz-nm limit of electronic heterogeneity and nanostrip junctions in a Dirac material ZrTe5. A clear Dirac Fermion density transition, manifested as the exclusive THz conductivity contrast, is quantitatively analyzed and profiled on both sides of the junction. This also allows the determination of variable junction width of ∼25–220 nm, depending on the THz conductivity contrast of adjacent strips. The unique THz-nm contrast is absent in mid-infrared nano-imaging measurements since topological semimetals with small Fermi pockets exhibit a better matching of their plasma frequency and scattering rate to the THz spectral region. The first-principles calculations provide two compelling implications: the conductivity nanocontrast can be induced by a small anisotropic strain, even less than 0.5%, due to an extreme strain sensitivity in ZrTe5; A nanoscale topological phase transition is realized across some junctions induced by the strain, between strong topological insulators (TIs) and weak TIs/Dirac semimetals (DSMs).

DOE Contract Number(s)

AC02-07CH11358

Language

en

Publisher

Iowa State University Digital Repository, Ames IA (United States)

Available for download on Thursday, May 19, 2022

Share

COinS