Fig. 7: Electrical transport properties of bismuth ultrathin 2D layer.

a Absorption spectrum for 1-nm bismuthene sample, showing tiny bandgap of ~0.2 eV. b Typical p-type transferring characteristic examined from one 10-nm-Bi-based FET. The inset shows 25 FETs evenly distributed across the centimeter plane of Bi ultrathin film. c Magnetic resistance performance of bismuth monocrystal with significant angular dependence that are investigated under different magnitudes of external magnetic field. d Schematics of two different edge types in bismuthene monolayer, showing by planar view and side view. e Point spectroscopy spectra of the dI/dV value as a function of the energies. Red, blue, and gray line are referred to the measurements along type A edge, along type B edge, and on the uniform surface, respectively. f, g Topographic line-cut feature and spectroscopy with energy line-scanning across and along the type A edge, respectively, which clearly exhibited the 1D edge state. Images of a and b used with permission from John Wiley and Sons⁴³. Image of c used with permission from Springer Nature¹³¹. Images of d–g used with permission from Springer Nature¹³⁷.