Speaker
Description
Crystal defects in topological insulators (TIs) are known to bind anomalous electronic states with two fewer dimensions than the bulk; the most commonly cited examples are the helical modes bound to screw dislocations in weak TIs. In this talk, we extend the classification of topological electronic defect states. By mapping the Hamiltonians of planes in momentum space to the real-space surfaces between screw or edge dislocations with integer Burgers vectors, we show that these crystalline defects can bind higher-order end states with fractional charge. We support our findings with extensive numerical calculations. Using density functional theory, we demonstrate the presence of first-order 0D defect states in PbTe monolayers, and HEND states in 3D SnTe crystals.
