Evolution of topological phases in atomically thin WTe2 films

Fuente: arXiv
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Hauptverfasser: Qiao, Changcang, Hsu, Chen-Chia, Zhang, Tao, Sun, Zhiming, Qian, Dong, Chan, Yang-hao, Chen, Peng
Format: Preprint
Veröffentlicht: 2026
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author Qiao, Changcang
Hsu, Chen-Chia
Zhang, Tao
Sun, Zhiming
Qian, Dong
Chan, Yang-hao
Chen, Peng
author_facet Qiao, Changcang
Hsu, Chen-Chia
Zhang, Tao
Sun, Zhiming
Qian, Dong
Chan, Yang-hao
Chen, Peng
contents Topological materials ranging from topological insulators to semimetals host many novel quantum phenomena including quantum spin Hall effect and topological Fermi arcs. Transitions between these topological phases have attracted much research interest. We performed angle-resolved photoemission spectroscopy (ARPES) on WTe2 ranging from a monolayer to the bulk and reveal the evolution of the electronic structure and the band gap. Notably, the gap observed in the monolayer system is suppressed in the three layers, where the film becomes metallic. Variations in the topological properties with thickness are demonstrated by the first-principles calculations. Topological Z2 invariant is shown to oscillate between 1 and 0 with the addition of layers, originating from the interlayer coupling-induced change in band crossing. The system evolves into a Weyl semimetal when the conduction and valence bands touch near the Fermi level and the topological nature is described by the Chern number. Our findings demonstrate the non-monotonic dependence of topological states on dimensionality and how layer-driven electronic band reconfiguration leads to phase transitions in solids.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16860
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Evolution of topological phases in atomically thin WTe2 films
Qiao, Changcang
Hsu, Chen-Chia
Zhang, Tao
Sun, Zhiming
Qian, Dong
Chan, Yang-hao
Chen, Peng
Mesoscale and Nanoscale Physics
Materials Science
Topological materials ranging from topological insulators to semimetals host many novel quantum phenomena including quantum spin Hall effect and topological Fermi arcs. Transitions between these topological phases have attracted much research interest. We performed angle-resolved photoemission spectroscopy (ARPES) on WTe2 ranging from a monolayer to the bulk and reveal the evolution of the electronic structure and the band gap. Notably, the gap observed in the monolayer system is suppressed in the three layers, where the film becomes metallic. Variations in the topological properties with thickness are demonstrated by the first-principles calculations. Topological Z2 invariant is shown to oscillate between 1 and 0 with the addition of layers, originating from the interlayer coupling-induced change in band crossing. The system evolves into a Weyl semimetal when the conduction and valence bands touch near the Fermi level and the topological nature is described by the Chern number. Our findings demonstrate the non-monotonic dependence of topological states on dimensionality and how layer-driven electronic band reconfiguration leads to phase transitions in solids.
title Evolution of topological phases in atomically thin WTe2 films
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2604.16860