Surface band bending on cleaved strongly correlated topological insulators*

Strongly correlated topological surface states are promising platforms for next-generation quantum applications, but they remain elusive in real materials. Although angle-resolved photoemission (ARPES) experiments on the correlated insulator SmB₆ appear to show spin-textured surface states, the Dirac point – the hallmark of any topological system – has not been resolved by ARPES. A key challenge is that SmB₆ lacks a natural cleaving plane, thus limiting the ordered surface domains to tens of nanometers, with local energy band features shifted by tens of meV as observed by our scanning tunneling microscopy experiments. Here we simulate the full spectral function as an average over multiple domains with different surface potentials and band-bending. We thus explain the discrepancy between large-area measurements that average over multiple band-shifted domains and atomically-resolved measurements.