# Rotation symmetry breaking in La2-xSrxCuO4 revealed by ARPES

## TL;DR

This study uses ARPES to reveal electronic reconstruction and symmetry breaking in La2-xSrxCuO4 near optimal doping, showing a specific wave vector q_a=(pi, 0) causes Fermi surface changes.

## Contribution

It uncovers a unique electronic reconstruction associated with a specific wave vector, demonstrating four-fold symmetry breaking in La2-xSrxCuO4.

## Key findings

- Reconstruction linked to wave vector q_a=(pi, 0)
- Absence of q_b reconstruction confirms symmetry breaking
- Distinct from shadow bands in other cuprates

## Abstract

Using angle-resolved photoemission spectroscopy it is revealed that in the vicinity of optimal doping the electronic structure of La2-xSrxCuO4 cuprate undergoes an electronic reconstruction associated with a wave vector q_a=(pi, 0). The reconstructed Fermi surface and folded band are distinct to the shadow bands observed in BSCCO cuprates and in underdoped La2-xSrxCuO4 with x <= 0.12, which shift the primary band along the zone diagonal direction. Furthermore the folded bands appear only with q_a=(pi, 0) vector, but not with q_b= (0, pi). We demonstrate that the absence of q_b reconstruction is not due to the matrix-element effects in the photoemission process, which indicates the four-fold symmetry is broken in the system.