Fermi Surface and Band Dispersion in La2-xSrxCuO4

TL;DR

This study uses ARPES to investigate how the Fermi surface and band structure in La2-xSrxCuO4 change with doping, revealing a transition from hole-like to electron-like Fermi surfaces and observing superconducting gaps.

Contribution

It provides detailed doping-dependent ARPES data on La2-xSrxCuO4, highlighting the Fermi surface evolution and spectral features distinct from other cuprates.

Findings

Fermi surface shifts from hole-like to electron-like with doping

Superconducting gap observed near (pi,0) in underdoped and optimally doped samples

Spectral peaks near (pi/2,pi/2) are broad and weak

Abstract

Using angle-resolved photoemission spectroscopy (ARPES), we have observed the band structure, Fermi surface and their doping dependences in La2-xSrxCuO4. The results reveal that the Fermi surface undergoes a dramatic change: it is hole-like and centered at k=(pi,pi) in underdoped (x = 0.1) and optimally doped (x = 0.15) samples as in other cuprates while it is electron-like and centered at (0,0) in heavily overdoped (x = 0.3) ones. The peak in the ARPES spectra near (pi/2,pi/2) is broad and weak unlike in other cuprates. In the underdoped and optimally doped samples, a superconducting gap (Delta = 10 - 15 meV) is observed on the Fermi surface near (pi,0).