Revealing the Thermal Properties of Superconducting Magic-Angle Twisted Bilayer Graphene

Abstract

The allegedly unconventional superconducting phase of magic-angle twisted bilayer graphene (MATBG) has been predicted to possess extraordinary thermal properties, as it is formed from a highly diluted electron ensemble with a record-low carrier density (n) of ∼10 11 cm −2 and electronic heat capacity (C e ) of <100k B . While these attributes position MATBG as a groundbreaking material platform for revolutionary calorimetric applications, these properties have so far not been experimentally shown.Here, we reveal the thermal properties of superconducting MATBG by monitoring its temperature dependent critical current (I c ) under continuous laser heating at 1550 nm. From the bolometric effect, we extract the temperature dependence of the electronic thermal conductance (G th ), which has a value of G th = 0.2 pW/K at 35 mK and in the low temperature limit is consistent with a power law dependence, as expected for nodal superconductors. Our work lays the foundation for future thermal transport studies on this system.

Ultrafast Umklapp-assisted electron-phonon cooling in magic-angle twisted bilayer graphene

“…[16,40] Finally, the ultrafast Umklapp-assisted electron-phonon cooling, enhanced density of states, and rich phase diagram are appealing for single-photon detection in the highly sought after mid-IR wavelength range. [44,45]…”

Symmetric Kondo Lattice States in Doped Strained Twisted Bilayer Graphene

“…The experiments on magic-angle (θ = 1.05 • ) twisted bilayer graphene (MATBLG) [4][5][6] have established the existence of a variety of interesting phases , including correlated insulating phases [29][30][31][32][33][34][35][36][37][38][39] and superconductivity [40][41][42][43][44]. Their discovery has been followed by considerable theoretical efforts aimed at understanding their origin.…”

Twist-Angle-Dependent Phonon Transport of van der Waals MoSe2 Thermoelectric Materials for the Recycling of Waste Heat

“…12−15 Except for the way of adjusting thermal conductivity, such as porosity design, 16,17 doping, 18 grain refinement, 19,20 and defects, 21,22 weak van der Waals (vdW) connections between layers make interlayer twist a reliable approach for regulating the thermal conductivity of layered 2D materials. 23−27 Di Battista et al 28 demonstrated that the magic-angle twisted bilayer graphene can obtain the coexistence of ultralow electronic heat capacity, thermal conductance, and carrier density. Cheng et al 29 discovered that different stacking modes of twisted graphene produce phonon scattering sites that lower the thermal conductivity.…”

“…As a novel category of layered materials, 2D transition-metal dichalcogenides (TMDCs), which can be expressed as MX 2 (M = Mo, W, Ti, and X = S, Se, Te), have been proven to be ideal candidates for advanced thermoelectric materials due to their relatively high electrical conductivity, low thermal conductivity, high Seebeck coefficient, and wide tunability of the inherent thermoelectric parameters. − Except for the way of adjusting thermal conductivity, such as porosity design, , doping, grain refinement, , and defects, , weak van der Waals (vdW) connections between layers make interlayer twist a reliable approach for regulating the thermal conductivity of layered 2D materials. − Di Battista et al demonstrated that the magic-angle twisted bilayer graphene can obtain the coexistence of ultralow electronic heat capacity, thermal conductance, and carrier density. Cheng et al discovered that different stacking modes of twisted graphene produce phonon scattering sites that lower the thermal conductivity.…”