2025/12/11 by Espitia, Giovanny, Lee, Seung Hun, Chiu, Calvin Kaiyu +2
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Strongly Correlated Electrons (cond-mat.str-el)
paper · doi:10.48550/arxiv.2512.11137
Two-dimensional moiré materials offer a powerful, twist-tunable platform for engineering electronic bands and correlations, though most studies to date have focused on small twist angles where flat bands arise from symmetry-pinned monolayer momenta. Here, we observe the surprising emergence of flat electronic bands with a distinctive quasi-one-dimensional dispersion at large twist angles in bilayer transition metal dichalcogenides that originate from the Λ valley states at generic momenta between Γ and K points. These taco-shaped anisotropic bands result from optimal interlayer hybridization between like-spin Λ valleys at the conduction band minimum in the Brillouin zone, resulting in directional band flattening at a magic twist-angle of 21.8∘. The bands form six anisotropic channels with a sixfold alternating spin texture reminiscent of altermagnetic textures. At low energies, the density of states shows a power-law dependence due to the quasi-one-dimensional character, enhancing the potential for correlated phases. Our results provide a new platform for correlated phenomena and broaden the scope of moiré engineering to large twist angles in 2D materials.