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

    Authors

    H. P. Paudel;M. N. Leuenberger

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    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

    Share

    COinS