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arXiv:2407.15916 · Physical review. B./Physical review. B

Boundary and defect criticality in topological insulators and superconductors

Xiaoyang Shen, Zhengzhi Wu, Shao-Kai Jian

Published Jun 26, 2025• 5 citations
arXivHTMLPDF

Abstract

We study the boundary criticality enriched by boundary fermions, which ubiquitously emerge in topological phases of matter, with a focus on topological insulators and topological superconductors. By employing dimensional regularization and bosonization techniques, we uncover several unprecedented boundary universality classes. These include the boundary Gross-Neveu-Yukawa critical point and the special Berezinskii-Kosterlitz-Thouless (BKT) transition, both resulting from the interplay between edge modes and bulk bosons. We present a comprehensive sketch of the phase diagram that accommodates these boundary criticalities and delineate their critical exponents. Additionally, we explore a 1+1D conformal defect decorated with fermions, where a defect BKT transition is highlighted. We conclude with a discussion on potential experimental realizations of these phenomena.

DOI
10.1103/4lv4-mc81

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