Extended Data Fig. 5: Observation of time-reversal-symmetry-protected edge states for different edge configurations.
From: Topological excitonic insulator with tunable momentum order
a, dI/dV maps acquired at different bias voltages (corresponding topography is shown in the bottom panel) around a monolayer step edge parallel to the c-axis measured at T = 5 K. The height profile perpendicular to the c-axis is also displayed. The dI/dV map obtained within the energy gap (V = 0 mV) reveals a pronounced edge state, whereas at V = 210 mV, the edge state is suppressed. b, Tunneling spectra acquired at locations away from the step edge and on the step edge measured under various magnetic fields. The orange and violet curves represent the differential spectra obtained at the step edge and away from it, respectively. The corresponding spatial locations where the spectra are acquired are marked with color-coded dots on the topographic image in panel a. Spectra at different magnetic fields were collected at the same locations and are vertically offset for clarity. Dashed horizontal lines mark the zero dI/dV for different fields. c, dI/dV maps acquired at different bias voltages (corresponding topography is shown in the bottom panel) around a four-layer step edge parallel to the b-axis direction. The height profile perpendicular to the b-axis is also shown. The dI/dV map obtained within the energy gap (V = 0 mV) reveals a pronounced edge state, whereas at V = 210 mV, the edge state is suppressed. d, Tunneling spectra acquired at locations away from the step edge and on the step edge measured under various magnetic fields. The orange and violet curves represent the differential spectra taken at the step edge and away from it, respectively. The corresponding spatial locations where the spectra are acquired are marked with color-coded dots on the topographic image in panel a. Spectra at different magnetic fields were taken at the same locations and are vertically offset for clarity. Dashed horizontal lines mark the zero dI/dV for different fields. Tunneling junction set-up: Vset = 300 mV, Iset = 0.5 nA, Vmod = 2 mV.
