Complex band structures of transition metal dichalcogenide monolayers with spin-orbit coupling effects

Dominik Szczȩśniak, Ahmed Ennaoui, Said Ahzi

Research output: Contribution to journalReview article

6 Citations (Scopus)

Abstract

Recently, the transition metal dichalcogenides have attracted renewed attention due to the potential use of their low-dimensional forms in both nano- and opto-electronics. In such applications, the electronic and transport properties of monolayer transition metal dichalcogenides play a pivotal role. The present paper provides a new insight into these essential properties by studying the complex band structures of popular transition metal dichalcogenide monolayers (MX2, where M = Mo, W; X = S, Se, Te) while including spin-orbit coupling effects. The conducted symmetry-based tight-binding calculations show that the analytical continuation from the real band structures to the complex momentum space leads to nonlinear generalized eigenvalue problems. Herein an efficient method for solving such a class of nonlinear problems is presented and yields a complete set of physically relevant eigenvalues. Solutions obtained by this method are characterized and classified into propagating and evanescent states, where the latter states manifest not only monotonic but also oscillatory decay character. It is observed that some of the oscillatory evanescent states create characteristic complex loops at the direct band gap of MX2 monolayers, where electrons can directly tunnel between the band gap edges. To describe these tunneling currents, decay behavior of electronic states in the forbidden energy region is elucidated and their importance within the ballistic transport regime is briefly discussed.

Original languageEnglish
Article number355301
JournalJournal of Physics Condensed Matter
Volume28
Issue number35
DOIs
Publication statusPublished - 1 Jul 2016

Fingerprint

Orbit
Band structure
Transition metals
Monolayers
Orbits
Metals
transition metals
orbits
Energy gap
eigenvalues
electronics
Electronic states
Ballistics
Electronic properties
Transport properties
Momentum
Tunnels
decay
Electronic equipment
Electrons

Keywords

  • computation methods
  • electronic properties
  • tunneling currents

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Complex band structures of transition metal dichalcogenide monolayers with spin-orbit coupling effects. / Szczȩśniak, Dominik; Ennaoui, Ahmed; Ahzi, Said.

In: Journal of Physics Condensed Matter, Vol. 28, No. 35, 355301, 01.07.2016.

Research output: Contribution to journalReview article

@article{10c36ad2e5f44f87956071ae1ff998e3,
title = "Complex band structures of transition metal dichalcogenide monolayers with spin-orbit coupling effects",
abstract = "Recently, the transition metal dichalcogenides have attracted renewed attention due to the potential use of their low-dimensional forms in both nano- and opto-electronics. In such applications, the electronic and transport properties of monolayer transition metal dichalcogenides play a pivotal role. The present paper provides a new insight into these essential properties by studying the complex band structures of popular transition metal dichalcogenide monolayers (MX2, where M = Mo, W; X = S, Se, Te) while including spin-orbit coupling effects. The conducted symmetry-based tight-binding calculations show that the analytical continuation from the real band structures to the complex momentum space leads to nonlinear generalized eigenvalue problems. Herein an efficient method for solving such a class of nonlinear problems is presented and yields a complete set of physically relevant eigenvalues. Solutions obtained by this method are characterized and classified into propagating and evanescent states, where the latter states manifest not only monotonic but also oscillatory decay character. It is observed that some of the oscillatory evanescent states create characteristic complex loops at the direct band gap of MX2 monolayers, where electrons can directly tunnel between the band gap edges. To describe these tunneling currents, decay behavior of electronic states in the forbidden energy region is elucidated and their importance within the ballistic transport regime is briefly discussed.",
keywords = "computation methods, electronic properties, tunneling currents",
author = "Dominik Szczȩśniak and Ahmed Ennaoui and Said Ahzi",
year = "2016",
month = "7",
day = "1",
doi = "10.1088/0953-8984/28/35/355301",
language = "English",
volume = "28",
journal = "Journal of Physics Condensed Matter",
issn = "0953-8984",
publisher = "IOP Publishing Ltd.",
number = "35",

}

TY - JOUR

T1 - Complex band structures of transition metal dichalcogenide monolayers with spin-orbit coupling effects

AU - Szczȩśniak, Dominik

AU - Ennaoui, Ahmed

AU - Ahzi, Said

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Recently, the transition metal dichalcogenides have attracted renewed attention due to the potential use of their low-dimensional forms in both nano- and opto-electronics. In such applications, the electronic and transport properties of monolayer transition metal dichalcogenides play a pivotal role. The present paper provides a new insight into these essential properties by studying the complex band structures of popular transition metal dichalcogenide monolayers (MX2, where M = Mo, W; X = S, Se, Te) while including spin-orbit coupling effects. The conducted symmetry-based tight-binding calculations show that the analytical continuation from the real band structures to the complex momentum space leads to nonlinear generalized eigenvalue problems. Herein an efficient method for solving such a class of nonlinear problems is presented and yields a complete set of physically relevant eigenvalues. Solutions obtained by this method are characterized and classified into propagating and evanescent states, where the latter states manifest not only monotonic but also oscillatory decay character. It is observed that some of the oscillatory evanescent states create characteristic complex loops at the direct band gap of MX2 monolayers, where electrons can directly tunnel between the band gap edges. To describe these tunneling currents, decay behavior of electronic states in the forbidden energy region is elucidated and their importance within the ballistic transport regime is briefly discussed.

AB - Recently, the transition metal dichalcogenides have attracted renewed attention due to the potential use of their low-dimensional forms in both nano- and opto-electronics. In such applications, the electronic and transport properties of monolayer transition metal dichalcogenides play a pivotal role. The present paper provides a new insight into these essential properties by studying the complex band structures of popular transition metal dichalcogenide monolayers (MX2, where M = Mo, W; X = S, Se, Te) while including spin-orbit coupling effects. The conducted symmetry-based tight-binding calculations show that the analytical continuation from the real band structures to the complex momentum space leads to nonlinear generalized eigenvalue problems. Herein an efficient method for solving such a class of nonlinear problems is presented and yields a complete set of physically relevant eigenvalues. Solutions obtained by this method are characterized and classified into propagating and evanescent states, where the latter states manifest not only monotonic but also oscillatory decay character. It is observed that some of the oscillatory evanescent states create characteristic complex loops at the direct band gap of MX2 monolayers, where electrons can directly tunnel between the band gap edges. To describe these tunneling currents, decay behavior of electronic states in the forbidden energy region is elucidated and their importance within the ballistic transport regime is briefly discussed.

KW - computation methods

KW - electronic properties

KW - tunneling currents

UR - http://www.scopus.com/inward/record.url?scp=84979586836&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84979586836&partnerID=8YFLogxK

U2 - 10.1088/0953-8984/28/35/355301

DO - 10.1088/0953-8984/28/35/355301

M3 - Review article

VL - 28

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

SN - 0953-8984

IS - 35

M1 - 355301

ER -