Twisted TMDs in the small-angle limit: exponentially flat and trivial bands
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| Format: | Preprint |
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2024
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| _version_ | 1866913192486109184 |
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| author | Becker, Simon Yang, Mengxuan |
| author_facet | Becker, Simon Yang, Mengxuan |
| contents | Recent experiments discovered fractional Chern insulator states at zero magnetic field in twisted bilayer MoTe$_2$ [C23,Z23] and WSe$_2$ [MD23]. In this article, we study the MacDonald Hamiltonian for twisted transition metal dichalcogenides (TMDs) and analyze the low-lying spectrum in TMDs in the limit of small twisting angles. Unlike in twisted bilayer graphene Hamiltonians, we show that TMDs do not exhibit flat bands. The flatness in TMDs for small twisting angles is due to spatial confinement by a matrix-valued potential. We show that by generalizing semiclassical techniques developed by Simon [Si83] and Helffer-Sjöstrand [HS84] to matrix-valued potentials, there exists a wide range of model parameters such that the low-lying bands are of exponentially small width in the twisting angle, topologically trivial, and obey a harmonic oscillator-type spacing with explicit parameters. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_06078 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Twisted TMDs in the small-angle limit: exponentially flat and trivial bands Becker, Simon Yang, Mengxuan Mathematical Physics Mesoscale and Nanoscale Physics Strongly Correlated Electrons Analysis of PDEs Spectral Theory Recent experiments discovered fractional Chern insulator states at zero magnetic field in twisted bilayer MoTe$_2$ [C23,Z23] and WSe$_2$ [MD23]. In this article, we study the MacDonald Hamiltonian for twisted transition metal dichalcogenides (TMDs) and analyze the low-lying spectrum in TMDs in the limit of small twisting angles. Unlike in twisted bilayer graphene Hamiltonians, we show that TMDs do not exhibit flat bands. The flatness in TMDs for small twisting angles is due to spatial confinement by a matrix-valued potential. We show that by generalizing semiclassical techniques developed by Simon [Si83] and Helffer-Sjöstrand [HS84] to matrix-valued potentials, there exists a wide range of model parameters such that the low-lying bands are of exponentially small width in the twisting angle, topologically trivial, and obey a harmonic oscillator-type spacing with explicit parameters. |
| title | Twisted TMDs in the small-angle limit: exponentially flat and trivial bands |
| topic | Mathematical Physics Mesoscale and Nanoscale Physics Strongly Correlated Electrons Analysis of PDEs Spectral Theory |
| url | https://arxiv.org/abs/2401.06078 |