Thermoelectric amplification of phonons in graphene

Анотація

Amplification of acoustic in-plane phonons due to an external temperature gradient (∇T) in single-layer graphene (SLG) was studied theoretically. The threshold temperature gradient (∇T)₀^g and the threshold voltage (V_T)₀^g in SLG were evaluated. For T = 77 K, the calculated value for (∇T)₀^g 746.8 K/cm and (V_T)₀^g=6.6mV. The calculationwas done in the hypersound regime. Further, the dependence of the normalized amplification (Γ/Γ₀) on the frequency ω_q and ∇T/T were evaluated numerically and presented graphically. The calculated threshold temperature gradient (∇T)₀^g for SLG was higher than that obtained for homogeneous semiconductors (n-InSb)(∇T)₀^hom ≈10³ K/cm, superlattices (∇T)₀^SL = 384 K/cm, and cylindrical quantum wire (∇T)₀^cqw≈10² K/cm. This makes SLG a much better material for thermoelectric phonon amplification.