Light-induced thermal noise \textit{anomaly} governed by quantum metric
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arXiv
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913615505784832 |
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| author | Xiang, Longjun Zhang, Lei Chen, Jun Xu, Fuming Wei, Yadong Wang, Jian |
| author_facet | Xiang, Longjun Zhang, Lei Chen, Jun Xu, Fuming Wei, Yadong Wang, Jian |
| contents | Traditionally, thermal noise in electric currents, arising from thermal agitation, is expected to increase with temperature $T$ and disappear as $T$ approaches zero. Contrary to this expectation, we discover that the resonant DC thermal noise (DTN) in photocurrents not only persists at $T=0$ but also exhibits a divergence proportional to $1/T$. This thermal noise \textit{anomaly} arises from the unique electron-photon interactions near the Fermi surface, manifesting as the interplay between the inherent Fermi-surface property and the resonant optical selection rules of DTN, and thereby represents an unexplored noise regime. Notably, we reveal that this \textit{anomalous} DTN, especially in time-reversal-invariant systems, is intrinsically linked to the quantum metric. We illustrate this \textit{anomalous} DTN in massless Dirac materials, including two-dimensional graphene, the surfaces of three-dimensional topological insulators, and three-dimensional Weyl semimetals, where the quantum metric plays a pivotal role. Finally, we find that the total noise spectrum at low temperatures, which includes both the DC shot noise and the \textit{anomalous} DTN, will universally peak at $ω_p=2|μ|$ with $ω_p$ the frequency of light and $μ$ the chemical potential of the bulk crystals. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_12662 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Light-induced thermal noise \textit{anomaly} governed by quantum metric Xiang, Longjun Zhang, Lei Chen, Jun Xu, Fuming Wei, Yadong Wang, Jian Mesoscale and Nanoscale Physics Traditionally, thermal noise in electric currents, arising from thermal agitation, is expected to increase with temperature $T$ and disappear as $T$ approaches zero. Contrary to this expectation, we discover that the resonant DC thermal noise (DTN) in photocurrents not only persists at $T=0$ but also exhibits a divergence proportional to $1/T$. This thermal noise \textit{anomaly} arises from the unique electron-photon interactions near the Fermi surface, manifesting as the interplay between the inherent Fermi-surface property and the resonant optical selection rules of DTN, and thereby represents an unexplored noise regime. Notably, we reveal that this \textit{anomalous} DTN, especially in time-reversal-invariant systems, is intrinsically linked to the quantum metric. We illustrate this \textit{anomalous} DTN in massless Dirac materials, including two-dimensional graphene, the surfaces of three-dimensional topological insulators, and three-dimensional Weyl semimetals, where the quantum metric plays a pivotal role. Finally, we find that the total noise spectrum at low temperatures, which includes both the DC shot noise and the \textit{anomalous} DTN, will universally peak at $ω_p=2|μ|$ with $ω_p$ the frequency of light and $μ$ the chemical potential of the bulk crystals. |
| title | Light-induced thermal noise \textit{anomaly} governed by quantum metric |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2412.12662 |