Observation of quantum spin Hall states in Ta${}_2$Pd${}_3$Te${}_5$

Abstract

Two-dimensional topological insulators (2DTIs), which host the quantum spin Hall (QSH) effect, are one of the key materials in next-generation spintronic devices. To date, experimental evidence of the QSH effect has only been observed in a few materials, and thus, the search for new 2DTIs is at the forefront of physical and materials science. Here, we report experimental evidence of a 2DTI in the van der Waals material Ta${}_2$Pd${}_3$Te${}_5$. First-principles calculations show that each monolayer of Ta${}_2$Pd${}_3$Te${}_5$ is a 2DTI with weak interlayer interactions. Combined transport, angle-resolved photoemission spectroscopy, and scanning tunneling microscopy measurements confirm the existence of a band gap at the Fermi level and topological edge states inside the gap. These results demonstrate that Ta${}_2$Pd${}_3$Te${}_5$ is a promising material for fabricating spintronic devices based on the QSH effect.

6 pages, 3 figures

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Cited by in corpus (9)

• Quadrupole topological insulators in Ta2M3Te5 (M= Ni, Pd) monolayers
• A robust and tunable Luttinger liquid in correlated edge of transition-metal second-order topological insulator Ta${}_2$Pd${}_3$Te${}_5$
• Spontaneous gap opening and potential excitonic states in an ideal Dirac semimetal Ta${}_2$Pd${}_3$Te${}_5$
• Interfering Josephson diode effect in Ta2Pd3Te5 asymmetric edge interferometer
• Pressure-induced nontrivial $Z_2$ band topology and superconductivity in transition metal chalcogenide ${\mathrm{Ta}}_2{\mathrm{Ni}}_3{\mathrm{Te}}_5$
• Large spin Hall conductivity and excellent hydrogen evolution reaction activity in unconventional PtTe1.75 monolayer
• Weak antilocalization in the transition metal telluride Ta${}_2$Pd${}_3$Te${}_5$
• Layer-dependent Raman spectroscopy of ultrathin Ta${}_2$Pd${}_3$Te${}_5$
• Ta2Pd3Te5 topological thermometer