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In this talk I will describe how topology emerges in crystalline environments from the perspective of local orbitals and highlight subtleties which appear when characterizing topology protected by crystalline symmetry. I will introduce a new notion of a topological obstruction which is not protected by bulk energy gap closings in periodic boundary conditions, but only in systems with open boundaries, which we call boundary obstructed topological phases. We will describe in this context on a celebrated model - the quantized quadrupole insulator in two-dimensions.

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Raquel Queiroz, Weizmann Institute
Online via Zoom
Contact: S. Diehl