Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 4: Graphene, 2D and Twisted Materials
TT 4.3: Talk
Monday, March 9, 2026, 10:00–10:15, HSZ/0105
Quantum diffusion in twisted bilayer graphene — •Taher Rhouma and Guy Trambly de Laissardière — LPTM, CY Cergy Paris Univ / CNRS, Cergy-Pontoise, France.
The discovery of correlated insulating and superconducting phases arising from the flat bands of magic-angle twisted bilayer graphene (TBG) [1] has stimulated intense interest in their electronic properties. We present a theoretical study of the electronic structure and quantum transport in these flat-band states, incorporating the structural effects of local defects such as non-resonant scatterers. Our real-space method [2,3,4,5] fully accounts for the modification of the electronic structure by defects and for multiple-scattering effects in the conductivity. It shows, in particular, that because of the extremely low Fermi velocity in the flat bands, standard semiclassical Bloch–Boltzmann approaches break down. We present the impact of non-resonant short-range disorder, modeled as diagonal Anderson disorder [4,5] with on-site energies εi = ε0 ± Δ W, on the bandwidth, conductivity, focusing on the impact of filling on the quantum diffusion of twisted bilayer graphene close to the magic angle.
[1] Y. Cao, et al., Nature 556, 43 (2018); Nature 556, 80 (2018).
[2] F. Triozon, et al., Phys. Rev. B 65, 220202, (2002).
[3] O. Faizy Namarvar, et al., Phys. Rev. B 101, 245407 (2020).
[4] P. Guerrero, et al., Phys. Rev. Lett. 134, 126301, (2025).
[5] G. Trambly de Laissardière, et al., Physica E 175 116362 (2026).
Keywords: Andreson disorder; Twisted bilayer graphene; 2D Materials; Quantum transport