Signature of Schwinger's pair creation rate via radiation generated in graphene by strong electric current

Abstract

Electron -hole pairs are copuously created by an applied electric …eld near the Dirac point in graphene or similar 2D electronic systems. It was shown recently that for su¢ ciently large electric …elds E and ballistic times the I-V characteristics become strongly nonlinear due to Schwinger's pair creation rate, proportional to E 3=2 . Since there is no energy gap the radiation from the pairs' annihilation is enhanced. The spectrum of radiation is calculated and exhibits a maximum at ! = p eEvg=~. The angular and polarization dependence of the emitted photons with respect to the graphene sheet is quite distinctive. For very large currents the recombination rate becomes so large that it leads to the second Ohmic regime due to radiation friction.

Effects of strain on the Schwinger pair creation in graphene

“…To determine the angular dependence of the intensity of the Schwingers pair state, we consider the electronphoton coupling in terms of Feynman diagrams of quantum electro-dynamics [10]- [12]. We incorporate the electromagnetic field through the minimal coupling p −→ p − e A/c, treating the new vector potential term as a quantized perturbation H int in the full Hamiltonian…”

“…Recently, the optoelectronic properties [10][11][12] of graphene have been studied using a formulation based on treating the BCS state as the result of the creation of an electron-positron pair. This corresponds to the use of quantum electrodynamics as formulated by Schwinger [13].…”