Strain-induced two-dimensional topological crystalline insulator

Fuente: arXiv
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Main Authors: Jing, Liwei, Amini, Mohammad, Fumega, Adolfo O., Silveira, Orlando J., Lado, Jose L., Liljeroth, Peter, Kezilebieke, Shawulienu
Format: Preprint
Published: 2024
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author Jing, Liwei
Amini, Mohammad
Fumega, Adolfo O.
Silveira, Orlando J.
Lado, Jose L.
Liljeroth, Peter
Kezilebieke, Shawulienu
author_facet Jing, Liwei
Amini, Mohammad
Fumega, Adolfo O.
Silveira, Orlando J.
Lado, Jose L.
Liljeroth, Peter
Kezilebieke, Shawulienu
contents Topological crystalline insulators (TCIs) host topological phases of matter protected by crystal symmetries. Topological surface states in three-dimensional TCIs have been predicted and observed in IV-VI SnTe-class semiconductors. Despite the prediction of a two-dimensional (2D) TCI characterized by two pairs of edge states inside the bulk gap, materials challenges have thus far prevented its experimental realization. Here we report the growth and characterization of bilayer SnTe on the 2$H$-NbSe$_2$ substrate by molecular beam epitaxy and scanning tunneling microscopy. We experimentally observe two anticorrelated, periodically modulated pairs of conducting edge states along the perimeters of the sample with a large band gap exceeding $0.2$ eV. We identify these states with a 2D TCI through first principles calculations. Finally, we probe the coupling of adjacent topological edge states and demonstrate the resulting energy shift driven by a combination of electrostatic interactions and tunneling coupling. Our work opens the door to investigations of tunable topological states in 2D TCIs, of potential impact for spintronics and nanoelectronics applications at room temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2410_06661
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Strain-induced two-dimensional topological crystalline insulator
Jing, Liwei
Amini, Mohammad
Fumega, Adolfo O.
Silveira, Orlando J.
Lado, Jose L.
Liljeroth, Peter
Kezilebieke, Shawulienu
Mesoscale and Nanoscale Physics
Materials Science
Topological crystalline insulators (TCIs) host topological phases of matter protected by crystal symmetries. Topological surface states in three-dimensional TCIs have been predicted and observed in IV-VI SnTe-class semiconductors. Despite the prediction of a two-dimensional (2D) TCI characterized by two pairs of edge states inside the bulk gap, materials challenges have thus far prevented its experimental realization. Here we report the growth and characterization of bilayer SnTe on the 2$H$-NbSe$_2$ substrate by molecular beam epitaxy and scanning tunneling microscopy. We experimentally observe two anticorrelated, periodically modulated pairs of conducting edge states along the perimeters of the sample with a large band gap exceeding $0.2$ eV. We identify these states with a 2D TCI through first principles calculations. Finally, we probe the coupling of adjacent topological edge states and demonstrate the resulting energy shift driven by a combination of electrostatic interactions and tunneling coupling. Our work opens the door to investigations of tunable topological states in 2D TCIs, of potential impact for spintronics and nanoelectronics applications at room temperature.
title Strain-induced two-dimensional topological crystalline insulator
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2410.06661