Publication Date

2-5-2019

Department

Ames Laboratory; Physics and Astronomy

Campus Units

Physics and Astronomy, Ames Laboratory

OSTI ID+

1494932

Report Number

IS-J 9887

DOI

10.1038/s41467-019-08559-6

Journal Title

Nature Communications

Volume Number

10

Issue Number

1

First Page

607

Abstract

Topology-protected surface transport of ultimate thinness in three-dimensional topological insulators (TIs) is breaking new ground in quantum science and technology. Yet a challenge remains on how to disentangle and selectively control surface helical spin transport from the bulk contribution. Here we use the mid-infrared and terahertz (THz) photoexcitation of exclusive intraband transitions to enable ultrafast manipulation of surface THz conductivity in Bi2Se3. The unique, transient electronic state is characterized by frequency-dependent carrier relaxations that directly distinguish the faster surface channel than the bulk with no complication from interband excitations or need for reduced bulk doping. We determine the topological enhancement ratio between bulk and surface scattering rates, i.e., γBS/γSS ~3.80 in equilibrium. The ultra-broadband, wavelength-selective pumping may be applied to emerging topological semimetals for separation and control of the protected transport connected with the Weyl nodes from other bulk bands.

DOE Contract Number(s)

AC02-07CH11358

Language

en

Department of Energy Subject Categories

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Publisher

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

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