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arXiv · 1712.06561

Soft pair excitations and double-log divergences due to carrier interactions in graphene

Cyprian Lewandowski·L. S. Levitov
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Abstract

Interactions between charge carriers in graphene lead to logarithmic renormalization of observables mimicking the behavior known in (3+1)-dimensional quantum electrodynamics (QED). Here we analyze soft electron-hole (e-h) excitations generated as a result of fast charge dynamics, a direct analog of the signature QED effect - multiple soft photons produced by the QED vacuum shakeup. We show that such excitations are generated in photon absorption, when a photogenerated high-energy e-h pair cascades down in energy and gives rise to multiple soft e-h excitations. This fundamental process is manifested in a double-log divergence in the emission rate of soft pairs and a characteristic power-law divergence in their energy spectrum of the form $\frac{1}ω\ln \left(\fracωΔ\right) $. Strong carrier-carrier interactions make pair production a prominent pathway in the photoexcitation cascade.

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Cyprian Lewandowski, L. S. Levitov. 2018-03-19. Soft pair excitations and double-log divergences due to carrier interactions in graphene. https://doi.org/10.1103/physrevb.97.115423

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