We have fabricated a 180∘-twisted bilayer ReSe2 by stacking two centrosymmetric monolayer ReSe2 flakes in opposite directions, which is expected to lose spatial inversion symmetry. By the second harmonic generation and angle-resolved photoemission spectroscopy, we successfully observed spatial inversion symmetry breaking and emergent band dispersions. The band calculation shows the finite lifting of spin degeneracy (~50 meV) distinct from natural monolayer and bilayer ReSe2. Our results demonstrate that the spin-momentum locked state, which leads to spintronic functions and Berry-curvature-related phenomena, can be realized even with the stacking of centrosymmetric monolayers.
@article{arxiv.2309.15403,
title = {180$^\circ$-twisted bilayer ReSe$_2$ as an artificial noncentrosymmetric semiconductor},
author = {S. Akatsuka and M. Sakano and T. Yamamoto and T. Nomoto and R. Arita and R. Murata and T. Sasagawa and K. Watanabe and T. Taniguchi and M. Kitamura and K. Horiba and K. Sugawara and S. Souma and T. Sato and H. Kumigashira and K. Shinokita and H. Wang and K. Matsuda and S. Masubuchi and T. Machida and K. Ishizaka},
journal= {arXiv preprint arXiv:2309.15403},
year = {2023}
}