Valley resolved optical spectroscopy and coherent excitation of quantum Hall edge states in graphene
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arXiv
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| Hauptverfasser: | , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866916814287536128 |
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| author | Singh, Ashutosh Sebastian, Maria Tokman, Mikhail Belyanin, Alexey |
| author_facet | Singh, Ashutosh Sebastian, Maria Tokman, Mikhail Belyanin, Alexey |
| contents | We show that chiral edge states in graphene under Quantum Hall effect conditions can be selectively probed and excited by terahertz or infrared radiation with single-quasiparticle sensitivity without affecting bulk states. Moreover, valley-selective excitation of edge states is possible with high fidelity. The underlying physical mechanism is the inevitable violation of adiabaticity and inversion symmetry breaking for electron states near the edge. This leads to the formation of Landau level-specific and valley-specific absorbance spectral peaks that are spectrally well separated from each other and from absorption by the bulk states, and have different polarization selection rules. Furthermore, inversion symmetry breaking enables coherent driving of chiral edge photocurrents due to second-order nonlinear optical rectification which becomes allowed in the electric dipole approximation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_19654 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Valley resolved optical spectroscopy and coherent excitation of quantum Hall edge states in graphene Singh, Ashutosh Sebastian, Maria Tokman, Mikhail Belyanin, Alexey Mesoscale and Nanoscale Physics We show that chiral edge states in graphene under Quantum Hall effect conditions can be selectively probed and excited by terahertz or infrared radiation with single-quasiparticle sensitivity without affecting bulk states. Moreover, valley-selective excitation of edge states is possible with high fidelity. The underlying physical mechanism is the inevitable violation of adiabaticity and inversion symmetry breaking for electron states near the edge. This leads to the formation of Landau level-specific and valley-specific absorbance spectral peaks that are spectrally well separated from each other and from absorption by the bulk states, and have different polarization selection rules. Furthermore, inversion symmetry breaking enables coherent driving of chiral edge photocurrents due to second-order nonlinear optical rectification which becomes allowed in the electric dipole approximation. |
| title | Valley resolved optical spectroscopy and coherent excitation of quantum Hall edge states in graphene |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2506.19654 |