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| Formato: | Preprint |
| Publicado: |
2025
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| Acceso en línea: | https://arxiv.org/abs/2508.07213 |
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| _version_ | 1866914525384540160 |
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| author | Kim, Youngjae |
| author_facet | Kim, Youngjae |
| contents | The selective control of specific momentum valleys lies at the core of valleytronics, a field that has thus far focused primarily on the $\mathbf{K}$ and $\mathbf{K'}$ valleys in transition metal dichalcogenides (TMDs). However, direct optical access to other low-lying yet conventionally inaccessible valleys such as the sixfold degenerate $\mathbf{Q}$ valleys has remained an outstanding challenge, fundamentally limiting the exploitation of the full valley degree of freedom for information processing. Here, we theoretically introduce an emergent light-wave valley selection rule that enables deterministic and high fidelity excitation of any single $\mathbf{Q}$ valley in monolayer TMDs. By coherently combining a circularly polarized pump pulse with a linearly polarized driver pulse, we engineer distinct quantum pathways that unambiguously excited electrons into a targeted $\mathbf{Q}$ valley, completely decoupled from the conventional $\mathbf{K}/\mathbf{K'}$ valleys. This all-optical scheme achieves near-unity ($\sim$100\%) valley polarization across an exceptionally broad ultrafast window, from the terahertz ($10^{12}$~Hz) to petahertz ($10^{15}$~Hz) regimes, enabling single $\mathbf{Q}$ valley polarization on femtosecond timescales. Our findings establish a new paradigm of light-wave quantum metrology in valleytronics, unlocking the $\mathbf{Q}$-valley subspace for scalable multi-state valley information processing. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_07213 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Light-Wave Engineering for Selective Polarization of a Single $\mathbf{Q}$ Valley in Transition Metal Dichalcogenides Kim, Youngjae Strongly Correlated Electrons Materials Science Optics The selective control of specific momentum valleys lies at the core of valleytronics, a field that has thus far focused primarily on the $\mathbf{K}$ and $\mathbf{K'}$ valleys in transition metal dichalcogenides (TMDs). However, direct optical access to other low-lying yet conventionally inaccessible valleys such as the sixfold degenerate $\mathbf{Q}$ valleys has remained an outstanding challenge, fundamentally limiting the exploitation of the full valley degree of freedom for information processing. Here, we theoretically introduce an emergent light-wave valley selection rule that enables deterministic and high fidelity excitation of any single $\mathbf{Q}$ valley in monolayer TMDs. By coherently combining a circularly polarized pump pulse with a linearly polarized driver pulse, we engineer distinct quantum pathways that unambiguously excited electrons into a targeted $\mathbf{Q}$ valley, completely decoupled from the conventional $\mathbf{K}/\mathbf{K'}$ valleys. This all-optical scheme achieves near-unity ($\sim$100\%) valley polarization across an exceptionally broad ultrafast window, from the terahertz ($10^{12}$~Hz) to petahertz ($10^{15}$~Hz) regimes, enabling single $\mathbf{Q}$ valley polarization on femtosecond timescales. Our findings establish a new paradigm of light-wave quantum metrology in valleytronics, unlocking the $\mathbf{Q}$-valley subspace for scalable multi-state valley information processing. |
| title | Light-Wave Engineering for Selective Polarization of a Single $\mathbf{Q}$ Valley in Transition Metal Dichalcogenides |
| topic | Strongly Correlated Electrons Materials Science Optics |
| url | https://arxiv.org/abs/2508.07213 |