Fig. 3: Scanning tunneling spectroscopies on the ZrTe5 monolayers.
From: Realization of monolayer ZrTe5 topological insulators with wide band gaps
a Differential conductance dI/dV spectra taken on the phase-I terrace away from the step edge (U = + 500 mV, It = 100 pA, the ac modulation voltage Umod = 8 mV). Inset: the same spectrum as (a) plotted with a logarithmic scale of the y-axis and a smaller linear scale of the x-axis. The positions of the valence band maximum (VBM) and conduction band minimum (CBM) are marked. b Comparison of two representative dI/dV spectra taken at the phase-I terrace (black) and at the step edge (red). The dI/dV spectrum taken at the bare graphene substrate (blue) is also plotted for comparison. c Spatially resolved dI/dV spectra (lower panel, U = + 500 mV, It = 100 pA, Umod = 8 mV) taken across the step edge along the gray arrowed line in the phase-I image (upper panel). d Decay of the edge state into the terrace from the step edge in phase I, as manifested by the line-cuts extracted from (c) at selective bias voltages. The according topographic line-scan profile is plotted in upper panel for comparison. The black solid lines in the bottom panel show the fit to an exponential decay as a guide to the eye. e–h Same as (a–d) but for phase II.
