Robust Coulomb Gap and Varied-temperature Study of Epitaxial 1T'-WSe$_2$ Monolayers

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Hauptverfasser: Chen, Wang, Hu, Mengli, Zong, Junyu, Xie, Xuedong, Ren, Wei, Meng, Qinghao, Yu, Fan, Tian, Qichao, Jin, Shaoen, Qiu, Xiaodong, Wang, Kaili, Wang, Can, Liu, Junwei, Li, Fang-Sen, Wang, Li, Zhang, Yi
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Veröffentlicht: 2024
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author Chen, Wang
Hu, Mengli
Zong, Junyu
Xie, Xuedong
Ren, Wei
Meng, Qinghao
Yu, Fan
Tian, Qichao
Jin, Shaoen
Qiu, Xiaodong
Wang, Kaili
Wang, Can
Liu, Junwei
Li, Fang-Sen
Wang, Li
Zhang, Yi
author_facet Chen, Wang
Hu, Mengli
Zong, Junyu
Xie, Xuedong
Ren, Wei
Meng, Qinghao
Yu, Fan
Tian, Qichao
Jin, Shaoen
Qiu, Xiaodong
Wang, Kaili
Wang, Can
Liu, Junwei
Li, Fang-Sen
Wang, Li
Zhang, Yi
contents The transition metal dichalcogenides (TMDCs) with a 1T' structural phase are predicted to be two-dimensional topological insulators at zero temperature. Although the quantized edge conductance of 1T'-WTe$_2$ has been confirmed to survive up to 100 K, this temperature is still relatively low for industrial applications. Addressing the limited studies on temperature effects in 1T'-TMDCs, our research focuses on the electronic and crystal properties of the epitaxial 1T'-WSe$_2$ monolayers grown on bilayer graphene (BLG) and SrTiO$_3$(100) substrates at various temperatures. For the 1T'-WSe$_2$ grown on BLG, we observed a significant thermal expansion effect on its band structures with a thermal expansion coefficient of $\sim$60$\times$10$^{-6}$ K$^{-1}$. In contrast, the 1T'-WSe$_2$ grown on SrTiO$_3$(100) exhibits minimal changes with varied temperatures due to the enhanced strain exerted by the substrate. Besides, A significant Coulomb gap (CG) was observed pinned at the Fermi level in the angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS). The CG was founded to decrease with increasing temperatures, and can persist up to 200 K for 1T'-WSe$_2$/BLG, consistent with our Monte Carlo simulations. The robustness of the CG and the positive fundamental gap endow the epitaxial 1T'-WSe$_2$ monolayers with huge potential for realizing the quantum spin Hall devices.
format Preprint
id arxiv_https___arxiv_org_abs_2409_09698
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Robust Coulomb Gap and Varied-temperature Study of Epitaxial 1T'-WSe$_2$ Monolayers
Chen, Wang
Hu, Mengli
Zong, Junyu
Xie, Xuedong
Ren, Wei
Meng, Qinghao
Yu, Fan
Tian, Qichao
Jin, Shaoen
Qiu, Xiaodong
Wang, Kaili
Wang, Can
Liu, Junwei
Li, Fang-Sen
Wang, Li
Zhang, Yi
Mesoscale and Nanoscale Physics
Materials Science
The transition metal dichalcogenides (TMDCs) with a 1T' structural phase are predicted to be two-dimensional topological insulators at zero temperature. Although the quantized edge conductance of 1T'-WTe$_2$ has been confirmed to survive up to 100 K, this temperature is still relatively low for industrial applications. Addressing the limited studies on temperature effects in 1T'-TMDCs, our research focuses on the electronic and crystal properties of the epitaxial 1T'-WSe$_2$ monolayers grown on bilayer graphene (BLG) and SrTiO$_3$(100) substrates at various temperatures. For the 1T'-WSe$_2$ grown on BLG, we observed a significant thermal expansion effect on its band structures with a thermal expansion coefficient of $\sim$60$\times$10$^{-6}$ K$^{-1}$. In contrast, the 1T'-WSe$_2$ grown on SrTiO$_3$(100) exhibits minimal changes with varied temperatures due to the enhanced strain exerted by the substrate. Besides, A significant Coulomb gap (CG) was observed pinned at the Fermi level in the angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS). The CG was founded to decrease with increasing temperatures, and can persist up to 200 K for 1T'-WSe$_2$/BLG, consistent with our Monte Carlo simulations. The robustness of the CG and the positive fundamental gap endow the epitaxial 1T'-WSe$_2$ monolayers with huge potential for realizing the quantum spin Hall devices.
title Robust Coulomb Gap and Varied-temperature Study of Epitaxial 1T'-WSe$_2$ Monolayers
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2409.09698