The electronic structure of La$_{1.48}$Nd$_{0.4}$Sr$_{0.12}$CuO$_4$ probed by high- and low-energy angle-resolved photoelectron spectroscopy: evolution with probing depth

TL;DR

This study uses high- and low-energy angle-resolved photoelectron spectroscopy to investigate the electronic structure of Nd-substituted cuprate La$_{1.48}$Nd$_{0.4}$Sr$_{0.12}$CuO$_4$, revealing differences between surface and bulk electronic structures and challenging previous findings of suppressed spectral weight.

Contribution

It provides new insights into the bulk electronic structure of Nd-LSCO by comparing surface-sensitive and bulk-sensitive photoemission data, showing spectral weight at all Fermi surface points and differences in Fermi surface shape.

Findings

Spectral weight observed at all Fermi surface points at both photon energies.

Differences in Fermi surface shape between low and high photon energies.

Evidence of intrinsic electronic structure differences between surface and bulk.

Abstract

We present angle-resolved photoelectron spectroscopy data probing the electronic structure of the Nd-substituted high-$T_c$ cuprate La$_{1.48}$Nd$_{0.4}$Sr$_{0.12}$CuO$_4$ (Nd-LSCO). Data have been acquired at low and high photon energies, $h\nu$ = 55 and 500 eV, respectively. Earlier comparable low-energy studies of La$_{1.4-x}$Nd$_{0.6}$Sr$_{x}$CuO$_4$ ($x = 0.10, 0.12, 0.15$) have shown strongly suppressed photoemission intensity, or absence thereof, in large parts of the Brillouin zone. Contrary to these findings we observe spectral weight at all points along the entire Fermi surface contour at low and high photon energies. No signs of strong charge modulations are found. At high photon energy, the Fermi surface shows obvious differences in shape as compared to the low-energy results presented here and in similar studies. The observed difference in shape and the high bulk-sensitivity at this photon energy suggest intrinsic electronic structure differences between the surface and bulk regions.