2020/10/25 by S. S. Kubakaddi, Kubakaddi, S. S.
Materials Science · Physics and Astronomy · #Carbon Nanotubes in Composites #FOS: Physical sciences #Graphene research and applications #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.2010.13019
arxiv created 2020/10/25 · openalex publication_date 2020/10/25 · arxiv updated 2020/10/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have carried out a theoretical investigation of hot electron power loss P, involving electron-acoustic phonon interaction, as a function of twist angle θ, electron temperature Te and electron density ns in twisted bilayer graphene (tBLG). It is found that as θ decreases closer to magic angle θm, P enhances strongly and θ acts as an important tunable parameter, apart from Te and ns. In the range of Te =1-50 K, this enhancement is ∼ 250-450 times the P in monolayer graphene (MLG), which is manifestation of the great suppression of Fermi velocity vF^* of electrons in moiré flat band. As θ increases away from θm, the impact of θ on P decreases, tending to that of MLG at θ ∼ 3∘. In the Bloch-Grüneisen (BG) regime, P ∼ Te4, ns-1/2 and vF*-2. In the higher temperature region (∼10- 50 K), P ∼ Teδ, with δ∼ 2.0, and the behavior is still super linear in Te, unlike the phonon limited linear-in- T ( lattice temperature) resistivity ρp. P is weakly, decreasing (increasing) with increasing ns at lower (higher) Te, as found in MLG. The energy relaxation time τe is also discussed as a function of θ and Te. Expressing the power loss P = Fe(Te)- Fe(T), in the BG regime, we have obtained a simple and useful relation Fe(T) μp (T) = (evs2/2) i.e. Fe(T) = (nse2 vs2/2)ρp, where μp is the acoustic phonon limited mobility and vs is the acoustic phonon velocity. The ρp estimated from this relation using our calculated Fe(T) is nearly agreeing with the ρp of Wu et al (Phys. Rev. B 99, 165112 (2019)).