Title

Giant Faraday effect due to Pauli exclusion principle in 3D topological insulators

Authors

Authors

H. P. Paudel;M. N. Leuenberger

Comments

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Abbreviated Journal Title

J. Phys.-Condes. Matter

Keywords

SINGLE DIRAC CONE; ELECTRON-SPIN; SURFACE; STATES; BI2TE3; GAP; HETEROJUNCTIONS; TRANSITION; BI2SE3; PHASE; Physics, Condensed Matter

Abstract

Experiments using ARPES, which is based on the photoelectric effect, show that the surface states in 3D topological insulators (TI) are helical. Here we consider Weyl interface fermions due to band inversion in narrow-bandgap semiconductors, such as Pb1-xSnxTe. The positive and negative energy solutions can be identified by means of opposite helicity in terms of the spin helicity operator in 3D TI as (h) over cap (TI) = (1/vertical bar p(perpendicular to)vertical bar) beta(sigma(perpendicular to) x p(perpendicular to)) . (z) over cap, where beta is a Dirac matrix and (z) over cap points perpendicular to the interface. Using the 3D Dirac equation and bandstructure calculations we show that the transitions between positive and negative energy solutions, giving rise to electron-hole pairs, obey strict optical selection rules. In order to demonstrate the consequences of these selection rules, we consider the Faraday effect due to the Pauli exclusion principle in a pump-probe setup using a 3D TI double interface of a PbTe/Pb0.31Sn0.69Te/PbTe heterostructure. For that we calculate the optical conductivity tensor of this heterostructure, which we use to solve Maxwell's equations. The Faraday rotation angle exhibits oscillations as a function of probe wavelength and thickness of the heterostructure. The maxima in the Faraday rotation angle are of the order of mrds.

Journal Title

Journal of Physics-Condensed Matter

Volume

26

Issue/Number

8

Publication Date

1-1-2014

Document Type

Article

Language

English

First Page

15

WOS Identifier

WOS:000331952100001

ISSN

0953-8984

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