Pressure-Driven Metallicity in Ångström-Thickness 2D Bismuth and Layer-Selective Ohmic Contact to MoS2

Fuente: arXiv
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Autori principali: Wang, Shuhua, Fang, Shibo, Li, Qiang, Yue, Yunliang, Yang, Zongmeng, Sun, Xiaotian, Lu, Jing, Lau, Chit Siong, Ang, L. K., Li, Lain-Jong, Ang, Yee Sin
Natura: Preprint
Pubblicazione: 2025
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author Wang, Shuhua
Fang, Shibo
Li, Qiang
Yue, Yunliang
Yang, Zongmeng
Sun, Xiaotian
Lu, Jing
Lau, Chit Siong
Ang, L. K.
Li, Lain-Jong
Ang, Yee Sin
author_facet Wang, Shuhua
Fang, Shibo
Li, Qiang
Yue, Yunliang
Yang, Zongmeng
Sun, Xiaotian
Lu, Jing
Lau, Chit Siong
Ang, L. K.
Li, Lain-Jong
Ang, Yee Sin
contents Recent fabrication of two-dimensional (2D) metallic bismuth (Bi) via van der Waals (vdW) squeezing method opens a new avenue to ultrascaling metallic materials into the ångström-thickness regime [Nature 639, 354 (2025)]. However, freestanding 2D Bi is typically known to exhibit a semiconducting phase [Nature 617, 67 (2023), Phys. Rev. Lett. 131, 236801 (2023)], which contradicts with the experimentally observed metallicity in vdW-squeezed 2D Bi. Here we show that such discrepancy originates from the pressure-induced buckled-to-flat structural transition in 2D Bi, which changes the electronic structure from semiconducting to metallic phases. Based on the experimentally fabricated MoS2-Bi-MoS2 trilayer heterostructure, we demonstrate the concept of layer-selective Ohmic contact in which one MoS2 layer forms Ohmic contact to the sandwiched Bi monolayer while the opposite MoS2 layer exhibits a Schottky barrier. The Ohmic contact can be switched between the two sandwiching MoS2 monolayers by changing the polarity of an external gate field, thus enabling charge to be spatially injected into different MoS2 layers. The layer-selective Ohmic contact proposed here represents a layertronic generalization of metal/semiconductor contact, paving a way towards layertronic device application.
format Preprint
id arxiv_https___arxiv_org_abs_2506_05133
institution arXiv
publishDate 2025
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spellingShingle Pressure-Driven Metallicity in Ångström-Thickness 2D Bismuth and Layer-Selective Ohmic Contact to MoS2
Wang, Shuhua
Fang, Shibo
Li, Qiang
Yue, Yunliang
Yang, Zongmeng
Sun, Xiaotian
Lu, Jing
Lau, Chit Siong
Ang, L. K.
Li, Lain-Jong
Ang, Yee Sin
Materials Science
Mesoscale and Nanoscale Physics
Applied Physics
Recent fabrication of two-dimensional (2D) metallic bismuth (Bi) via van der Waals (vdW) squeezing method opens a new avenue to ultrascaling metallic materials into the ångström-thickness regime [Nature 639, 354 (2025)]. However, freestanding 2D Bi is typically known to exhibit a semiconducting phase [Nature 617, 67 (2023), Phys. Rev. Lett. 131, 236801 (2023)], which contradicts with the experimentally observed metallicity in vdW-squeezed 2D Bi. Here we show that such discrepancy originates from the pressure-induced buckled-to-flat structural transition in 2D Bi, which changes the electronic structure from semiconducting to metallic phases. Based on the experimentally fabricated MoS2-Bi-MoS2 trilayer heterostructure, we demonstrate the concept of layer-selective Ohmic contact in which one MoS2 layer forms Ohmic contact to the sandwiched Bi monolayer while the opposite MoS2 layer exhibits a Schottky barrier. The Ohmic contact can be switched between the two sandwiching MoS2 monolayers by changing the polarity of an external gate field, thus enabling charge to be spatially injected into different MoS2 layers. The layer-selective Ohmic contact proposed here represents a layertronic generalization of metal/semiconductor contact, paving a way towards layertronic device application.
title Pressure-Driven Metallicity in Ångström-Thickness 2D Bismuth and Layer-Selective Ohmic Contact to MoS2
topic Materials Science
Mesoscale and Nanoscale Physics
Applied Physics
url https://arxiv.org/abs/2506.05133