Anomalous growth of thermoelectric power in gapped graphene

Abstract

There exist experiments indicating that at certain conditions, such as an appropriate substrate, a gap of the order of 10 meV can be opened at the Dirac points of a quasiparticle spectrum of graphene. We demonstrate that the opening of such a gap can result in the appearance of a fingerprint bump of the Seebeck signal when the chemical potential approaches the gap edge. The magnitude of the bump can be up to one order higher than the already large value of the thermopower occurring in graphene. Such a giant effect, accompanied by the nonmonotonous dependence on the chemical potential, is related to the emergence of a new channel of quasiparticle scattering from impurities with the relaxation time strongly dependent on the energy. We analyze the behavior of conductivity and thermopower in such a system, accounting for quasiparticle scattering from impurities with the model potential in a self-consistent scheme. Reproducing the existing results for the case of gapless graphene, we demonstrate a failure of the simple Mott formula in the case under consideration.

5 pages, 1 figure; final version published in PRB

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• Entropy spikes as a signature of Lifshitz transitions in the Dirac materials
• Thermoelectric effect enhanced by the resonant states in graphene
• Thermoelectric and thermospin transport in a ballistic junction of graphene
• Spin-dependent Seebeck effect and huge growth of thermoelectric parameters at band edges in H- and F-doped graphene, free-standing and deposited on 4H-SiC(0001) C-face
• Entropy per particle spikes in the transition metal dichalcogenides
• Entropy Signatures of Topological Phase Transitions
• Effect of Coulomb Interaction on Seebeck Coefficient of Organic Dirac Electron System $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Photo-induced spin and valley-dependent Seebeck effect in the low-buckled Dirac materials