Dimensional crossover of transport characteristics in topological insulator nanofilms

Koji Kobayashi, Yukinori Yoshimura, Ken Ichiro Imura, Tomi Ohtsuki

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

We show how the two-dimensional (2D) topological insulator evolves, by stacking, into a strong or weak topological insulator with different topological indices, proposing a new conjecture that goes beyond an intuitive picture of the crossover from quantum spin Hall to weak topological insulator. Studying the conductance under different boundary conditions, we demonstrate the existence of two conduction regimes in which conduction happens through either surface or edge conduction channels. We show that the two conduction regimes are complementary and exclusive. Conductance maps in the presence and absence of disorder are introduced, together with 2D Z2-index maps, describing the dimensional crossover of the conductance from the 2D to the 3D limit. Stacking layers is an effective way to invert the gap, an alternative to controlling the strength of spin-orbit coupling. The emerging quantum spin Hall insulator phase is not restricted to the case of odd numbers of layers.

Original languageEnglish
Article number235407
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume92
Issue number23
DOIs
Publication statusPublished - 2015 Dec 3
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Dimensional crossover of transport characteristics in topological insulator nanofilms'. Together they form a unique fingerprint.

Cite this