Enhanced Berry curvature dipole and persistent spin texture in Bi(110) monolayer

Non-vanishing Berry curvature dipole (BCD) and persistent spin texture (PST) are intriguing physical manifestations of electronic states in noncentrosymmetric 2D materials. The former induces a nonlinear Hall conductivity while the latter offers a coherent spin current. Based on density-functional-theory (DFT) calculations, we demonstrate the coexistence of both phenomena in a Bi(110) monolayer with a distorted phosphorene structure. Both effects are concurrently enhanced due to the strong spin-orbit coupling of Bi while the structural distortion creates internal in-plane ferroelectricity with inversion asymmetry. We further succeed in fabricating a Bi(110) monolayer in the desired phosphorene structure on NbSe₂ substrate. Detailed atomic and electronic structures of the Bi(110)/NbSe₂ heterostructure are characterized by scanning tunneling microscopy/spectroscopy and angle-resolved-photoemission spectroscopy. These results are consistent with DFT calculations which indicate the large BCD and PST retained. Our results suggest the Bi(110)/NbSe₂ heterostructure as a promising platform to exploit nonlinear Hall and coherent spin transport properties together.