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| Main Authors: | , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2409.03058 |
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Table of Contents:
- Hot, dense phases of Dirac fermions - predicted to resemble relativistic plasma - are uniquely accessible through photoexcitation of pristine, charge neutral graphene. We demonstrate a sensitive temperature probe of the photoexcited Dirac state, called interlayer optoelectronic thermometry, which measures out-of-plane transport of hot carriers in high-mobility, neutral graphene encapsulated within graphene-hBN-graphene heterostructures. At a critical intermediate sample temperature T = 50 K, the electronic temperature Te is quenched, exhibiting an intrinsic cooling rate that exceeds 10^14 Kelvin/s within the first picosecond after photoexcitation. Quenching is further enhanced by applying in-plane voltages within the stack-engineered heterostructure. Extreme sensitivity of Te to sample temperature and applied voltages reveals anomalously efficient hot-carrier quenching, which we identify as an essential feature of the strongly interacting hot Dirac excited state.