Interlayer electron-hole friction in tunable twisted bilayer graphene semimetal
arXiv:2208.05659 · doi:10.1103/PhysRevLett.129.206802
Abstract
Charge-neutral conducting systems represent a class of materials with unusual properties governed by electron-hole (e-h) interactions. Depending on the quasiparticles' statistics, band structure, and device geometry these semimetallic phases of matter can feature unconventional responses to external fields that often defy simple interpretations in terms of single-particle physics. Here we show that small-angle twisted bilayer graphene (SA-TBG) offers a highly-tunable system in which to explore interactions-limited electron conduction. By employing a dual-gated device architecture we tune our devices from a non-degenerate charge-neutral Dirac fluid to a compensated two-component e-h Fermi liquid where spatially separated electrons and holes experience strong mutual friction. This friction is revealed through the T^2 resistivity that accurately follows the e-h drag theory we develop. Our results provide a textbook illustration of a smooth transition between different interaction-limited transport regimes and clarify the conduction mechanisms in charge-neutral SA-TBG.
11 pages, 4 figures, supplementary information
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Cited by in corpus (7)
- Anomalous terahertz photoconductivity caused by the superballistic flow of hydrodynamic electrons in graphene
- Extreme electron-hole drag and negative mobility in the Dirac plasma of graphene
- Interaction dominated transport in 2D conductors: from degenerate to partially-degenerate regime
- Interaction-controlled transport in a two-dimensional massless-massive Dirac system: Transition from degenerate to nondegenerate regimes
- Electron-hole collision-limited resistance of gapped graphene
- Interactions-controlled magnetotransport in two-dimensional massless-massive fermion mixtures
- Dragging of electric current by hydrodynamic flow at charge neutrality