Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain

One-dimensional (1D) flat bands in low-dimensional materials enable the study of exotic correlated phases like bond density waves, Luttinger liquids, and Mott insulators. However, the underlying mechanisms driving their formation remain elusive, and achieving well-isolated 1D flat bands in readily a...

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Main Authors: Peng-Lai Gong, Zi-Ye Li, Shu-Hui Wang, Yao-Long Kang, Yu-Han Yang, Chen-Dong Jin, Jiang-Long Wang, Fang Zhang, Xing-Qiang Shi
Format: Article
Language:English
Published: American Physical Society 2025-07-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/xkwq-k2gp
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author Peng-Lai Gong
Zi-Ye Li
Shu-Hui Wang
Yao-Long Kang
Yu-Han Yang
Chen-Dong Jin
Jiang-Long Wang
Fang Zhang
Xing-Qiang Shi
author_facet Peng-Lai Gong
Zi-Ye Li
Shu-Hui Wang
Yao-Long Kang
Yu-Han Yang
Chen-Dong Jin
Jiang-Long Wang
Fang Zhang
Xing-Qiang Shi
author_sort Peng-Lai Gong
collection DOAJ
description One-dimensional (1D) flat bands in low-dimensional materials enable the study of exotic correlated phases like bond density waves, Luttinger liquids, and Mott insulators. However, the underlying mechanisms driving their formation remain elusive, and achieving well-isolated 1D flat bands in readily achievable systems remains a significant challenge. Here we present a versatile method for engineering tunable 1D flat bands in untwisted bilayer black phosphorus using asymmetric uniaxial strain to achieve differential strain in each layer. Our first-principles calculations reveal that both the highly anisotropic stacking pattern effect and the anisotropic intralayer orbital hybridization between moiré impurities (i.e., local stacking configurations) play critical roles in the formation of 1D flat bands. Notably, asymmetric armchair strain can generate 1D well-isolated flat bands at experimentally accessible strains owing to its pronounced stacking pattern effect. This configuration provides an opportunity to directly observe 1D flat band dispersion using angle-resolved photoemission spectroscopy. Furthermore, we demonstrate that transitioning from 1D to 2D flat bands is possible by applying asymmetric biaxial strain. Our work establishes asymmetric strain as a powerful tool for engineering flat bands in bilayer systems and opens new avenues for exploring 1D strongly correlated electron systems.
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spelling doaj-art-aaf76adc994f40baac53b3a6e80ac3102025-08-20T03:15:03ZengAmerican Physical SocietyPhysical Review Research2643-15642025-07-017303308110.1103/xkwq-k2gpDesigning one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strainPeng-Lai GongZi-Ye LiShu-Hui WangYao-Long KangYu-Han YangChen-Dong JinJiang-Long WangFang ZhangXing-Qiang ShiOne-dimensional (1D) flat bands in low-dimensional materials enable the study of exotic correlated phases like bond density waves, Luttinger liquids, and Mott insulators. However, the underlying mechanisms driving their formation remain elusive, and achieving well-isolated 1D flat bands in readily achievable systems remains a significant challenge. Here we present a versatile method for engineering tunable 1D flat bands in untwisted bilayer black phosphorus using asymmetric uniaxial strain to achieve differential strain in each layer. Our first-principles calculations reveal that both the highly anisotropic stacking pattern effect and the anisotropic intralayer orbital hybridization between moiré impurities (i.e., local stacking configurations) play critical roles in the formation of 1D flat bands. Notably, asymmetric armchair strain can generate 1D well-isolated flat bands at experimentally accessible strains owing to its pronounced stacking pattern effect. This configuration provides an opportunity to directly observe 1D flat band dispersion using angle-resolved photoemission spectroscopy. Furthermore, we demonstrate that transitioning from 1D to 2D flat bands is possible by applying asymmetric biaxial strain. Our work establishes asymmetric strain as a powerful tool for engineering flat bands in bilayer systems and opens new avenues for exploring 1D strongly correlated electron systems.http://doi.org/10.1103/xkwq-k2gp
spellingShingle Peng-Lai Gong
Zi-Ye Li
Shu-Hui Wang
Yao-Long Kang
Yu-Han Yang
Chen-Dong Jin
Jiang-Long Wang
Fang Zhang
Xing-Qiang Shi
Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
Physical Review Research
title Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
title_full Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
title_fullStr Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
title_full_unstemmed Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
title_short Designing one-dimensional well-isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
title_sort designing one dimensional well isolated flat bands in untwisted bilayer black phosphorus by asymmetric uniaxial strain
url http://doi.org/10.1103/xkwq-k2gp
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