Title: Electronic Reconstruction from Weak Coupling in Low Dimensions
Speaker: Dr. Aitor Garcia-Ruiz (Department of Physics, NCKU)
Time: 10:30-11:30, May 4 (Mon.), 2026
Place: NCTS Physics 4F Lecture Hall, Cosmology Hall, NTU

Abstract:
Low-dimensional materials provide a fertile ground for emergent electronic phases driven by the interplay of interactions, doping, and coupling. In this talk, I will discuss two complementary systems, one-dimensional (1D) atomic chains and large-angle twisted bilayer graphene (LAtBLG), that illustrate how weak coupling can qualitatively reshape correlated behavior.
In the first part, I present a 1D atomic chains within the Peierls framework, and show that inter-chain coupling, together with lattice geometry and carrier doping, controls the stability of charge density wave order and can even give rise to bistability between distinct lattice and electronic configurations. In the second part, I will turn to LAtBLG, often assumed to consist of effectively decoupled graphene layers. Contrary to this belief, recent low energy magnetotransport experiments reveal an unexpected angle dependence of the Hall conductivity near the maximal misalignment at 30 degrees. Using tight-binding modeling and large-scale quantum transport simulations, I discuss a possible microscopic origin for such dependence, in terms of interlayer-Umklapp scattering.