Fig. 2: Bulk-boundary correspondence in the QSHI indenene.
From: Backscattering in topological edge states despite time-reversal symmetry
a Ball and stick model (left) of indenene on SiC(0001) forming the three edge types (zigzag, flat A, flat B) at the boundary to H-saturated SiC. The inset highlights the carbon position in the top SiC layer, distinguishing flat edge B from flat edge A. STM topography (right) of an indenene edge consisting of zigzag and flat edge A segments, interrupted by kinks that act as scattering centers (IT = 300 pA, Vbias = 0.95 V). b Top: 3D visualization of a (32 nm)2 STM topography scan (IT = 10 pA, Vbias = −3 V) showing a hole with H-saturated SiC in an otherwise closed indenene film. Bottom: Corresponding dI/dV map highlighting edge states and taken at constant height by integrating states within Vbias = (0 ± 10) mV. c ARPES measurement and overlaid G0W0 bandstructure (reprinted from34) of indenene’s Dirac bands, illustrating band position and charge neutral doping. The inset shows an energy distribution curve at the K-point of indenene. d dI/dV line scan approaching an indenene zigzag edge, showing that metallic edge states (inset red curve) fill the 120 mV bulk gap (inset white curve). e Edge topography (black) and exponential decay of metallic edge states with a decay constant of ξ = (3.6 ± 0.6) Å fitted to the gap-integrated dI/dV signal (red dots). Tunneling parameters of (d, e) are IT = 50 pA, Vbias = 1 V, δz = −0.2 nm (d).
