# Topological corner modes in a brick lattice with nonsymmorphic symmetry

## TL;DR

This paper introduces a brick lattice model with nonsymmorphic symmetry that hosts topological corner modes, expanding the understanding of higher-order topological phases and proposing an experimental realization in RLC circuits.

## Contribution

It presents a new brick lattice model with unique symmetry protection and a novel topological invariant, broadening the class of higher-order topological insulators.

## Key findings

- Identified two topological regimes in the phase diagram.
- Demonstrated realization of corner modes in RLC circuits.
- Proposed detection via colossal topolectrical resonances.

## Abstract

The quest for new realizations of higher-order topological system has garnered much recent attention. In this work, we propose a paradigmatic brick lattice model where corner modes requires protection by nonsymmorphic symmetry in addition to two commuting mirror symmetries. Unlike the well-known square corner mode lattice, it has an odd number of occupied bands, which necessitates a different definition for the $\mathbb Z_2\times \mathbb Z_2$ topological invariant. By studying both the quadrupolar polarization and effective edge model, our study culminates in a phase diagram containing two distinct topological regimes. Our brick lattice corner modes can be realized in a RLC circuit setup and detected via collossal "topolectrical" resonances.