2019/10/07 by Phanibhusan S Mahapatra, Phanibhusan S. Mahapatra, Bhaskar Ghawri +7
Chemistry · Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #Bilayer #Bilayer graphene #Chemistry #Condensed matter physics #Graphene #Graphene research and applications #Materials science #Misorientation #Nanotechnology #Physics #Quantum mechanics #Seebeck coefficient #Thermal properties of materials #Thermoelectric effect #cond-mat.mes-hall #van der Waals force
paper · pdf · doi:10.1103/physrevlett.125.226802
5 figures
arxiv created 2019/10/07 · openalex publication_date 2020/11/24 · arxiv updated 2020/12/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The introduction of "twist" or relative rotation between two atomically thin van der Waals membranes gives rise to periodic moiré potential, leading to a substantial alteration of the band structure of the planar assembly. While most of the recent experiments primarily focus on the electronic-band hybridization by probing in-plane transport properties, here we report out-of-plane thermoelectric measurements across the van der Waals gap in twisted bilayer graphene, which exhibits an interplay of twist-dependent interlayer electronic and phononic hybridization. We show that at large twist angles, the thermopower is entirely driven by a novel phonon-drag effect at subnanometer scale, while the electronic component of the thermopower is recovered only when the misorientation between the layers is reduced to <6°. Our experiment shows that cross-plane thermoelectricity at low angles is exceptionally sensitive to the nature of band dispersion and may provide fundamental insights into the coherence of electronic states in twisted bilayer graphene.