Time, momentum, and energy resolved pump-probe tunneling spectroscopy of two-dimensional electron systems
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arXiv
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| Format: | Preprint |
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2023
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| author | Yoo, H. M. Korkusinski, M. Miravet, D. Baldwin, K. W. West, K. Pfeiffer, L. Hawrylak, P. Ashoori, R. C. |
| author_facet | Yoo, H. M. Korkusinski, M. Miravet, D. Baldwin, K. W. West, K. Pfeiffer, L. Hawrylak, P. Ashoori, R. C. |
| contents | Real-time probing of electrons can uncover intricate relaxation mechanisms and many-body interactions hidden in strongly correlated materials. While experimenters have used ultrafast optical pump-probe methods in bulk materials, laser heating and insensitivity below the surface prevent their application to encapsulated low-dimensional electron systems at millikelvin temperatures, home to numerous intriguing electronic phases. Here, we introduce time, momentum, and energy resolved pump-probe tunneling spectroscopy (Tr-MERTS). The method allows the injection of electrons at particular energies and observation of their subsequent decay in energy-momentum space. Using Tr-MERTS, we visualize electronic decay processes in Landau levels with lifetimes up to tens of microseconds. Although most observed features agree with simple energy-relaxation, we discover an unexpected splitting in the nonequilibrium energy spectrum in the vicinity of a ferromagnetic state. An exact diagonalization study of the system suggests that the splitting arises from a maximally spin-polarized higher energy state, distinct from a conventional equilibrium skyrmion. Furthermore, we observe time-dependent relaxation of the splitting, which we attribute to single-flipped spins forming topological spin textures. These results establish Tr-MERTS as a powerful tool for studying the dynamics and properties of a two-dimensional electronic system beyond equilibrium. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2304_12434 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Time, momentum, and energy resolved pump-probe tunneling spectroscopy of two-dimensional electron systems Yoo, H. M. Korkusinski, M. Miravet, D. Baldwin, K. W. West, K. Pfeiffer, L. Hawrylak, P. Ashoori, R. C. Mesoscale and Nanoscale Physics Real-time probing of electrons can uncover intricate relaxation mechanisms and many-body interactions hidden in strongly correlated materials. While experimenters have used ultrafast optical pump-probe methods in bulk materials, laser heating and insensitivity below the surface prevent their application to encapsulated low-dimensional electron systems at millikelvin temperatures, home to numerous intriguing electronic phases. Here, we introduce time, momentum, and energy resolved pump-probe tunneling spectroscopy (Tr-MERTS). The method allows the injection of electrons at particular energies and observation of their subsequent decay in energy-momentum space. Using Tr-MERTS, we visualize electronic decay processes in Landau levels with lifetimes up to tens of microseconds. Although most observed features agree with simple energy-relaxation, we discover an unexpected splitting in the nonequilibrium energy spectrum in the vicinity of a ferromagnetic state. An exact diagonalization study of the system suggests that the splitting arises from a maximally spin-polarized higher energy state, distinct from a conventional equilibrium skyrmion. Furthermore, we observe time-dependent relaxation of the splitting, which we attribute to single-flipped spins forming topological spin textures. These results establish Tr-MERTS as a powerful tool for studying the dynamics and properties of a two-dimensional electronic system beyond equilibrium. |
| title | Time, momentum, and energy resolved pump-probe tunneling spectroscopy of two-dimensional electron systems |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2304.12434 |