A general route to form topologically-protected surface and bulk Dirac fermions along high-symmetry lines

O. J. Clark, F. Mazzola, I. Marković, J. M. Riley, J. Feng, B. J. Yang, K. Sumida, T. Okuda, J. Fujii, I. Vobornik, Timur K. Kim, K. Okawa, T. Sasagawa, M. S. Bahramy, P. D.C. King

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

The band inversions that generate the topologically non-trivial band gaps of topological insulators and the isolated Dirac touching points of three-dimensional Dirac semimetals generally arise from the crossings of electronic states derived from different orbital manifolds. Recently, the concept of single orbital-manifold band inversions occurring along high-symmetry lines has been demonstrated, stabilising multiple bulk and surface Dirac fermions. Here, we discuss the underlying ingredients necessary to achieve such phases, and discuss their existence within the family of transition metal dichalcogenides. We show how their three-dimensional band structures naturally produce only small kz projected band gaps, and demonstrate how these play a significant role in shaping the surface electronic structure of these materials. We demonstrate, through spin- A nd angle-resolved photoemission and density functional theory calculations, how the surface electronic structures of the group-X TMDs PtSe2 and PdTe2 are host to up to five distinct surface states, each with complex band dispersions and spin textures. Finally, we discuss how the origin of several recently-realised instances of topological phenomena in systems outside of the TMDs, including the iron-based superconductors, can be understood as a consequence of the same underlying mechanism driving kz-mediated band inversions in the TMDs.

Original languageEnglish
Article number014002
JournalElectronic Structure
Volume1
Issue number1
DOIs
Publication statusPublished - Mar 2019

Bibliographical note

Funding Information:
We gratefully acknowledge support from the Leverhulme Trust (Grant No. RL-2016-006), the Royal Society, CREST, JST (Nos. JPMJCR16F1 and JPMJCR16F2), and the International Max-Planck Partnership for Measurement and Observation at the Quantum Limit. OJC acknowledges EPSRC for PhD studentship support through grant No. EP/K503162/1. IM acknowledges PhD studentship support from the IMPRS for the Chemistry and Physics of Quantum Materials. JF is supported by the Chinese Academy of Sciences Hundred Talents Program (No. Y8BED11001). B-JY was supported by the Institute for Basic Science in Korea (Grant No. IBS-R009-D1) and Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant No. 0426-20170012, No.0426-20180011), the POSCO Science Fellowship of POSCO TJ Park Foundation (No.0426-20180002), and the US Army Research Office under Grant Number W911NF-18-1-0137. This work was performed under the approval of Proposal Assessing Committee of HiSOR (Proposal No. 17BG022). This work has been partly performed in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MIUR, Italy) facility.We thank Diamond Light Source (via Proposal Nos.SI14927-1 and SI16262-1),HiSOR and Elettra Sincrotrone Trieste for access to the I05, BL9A and APE beamlines respectively that contributed to the results presented here. The research data supporting this publication can be accessed at [49].

Publisher Copyright:
©2019 IOP Publishing Ltd.

Keywords

  • Dirac semimetals
  • Spin-resolved ARPEs
  • Topological insulators
  • Transition metal dichalcogenides (TMDs)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry
  • Electrochemistry

Fingerprint

Dive into the research topics of 'A general route to form topologically-protected surface and bulk Dirac fermions along high-symmetry lines'. Together they form a unique fingerprint.

Cite this