Underlying Fermi surface of Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$ in two-dimensional momentum space observed by angle-resolved photoemission spectroscopy

TL;DR

This study uses angle-resolved photoemission spectroscopy to explore the Fermi surface and electronic structure of Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$, revealing quasi-one-dimensional behavior, charge density wave gaps, and carrier localization effects.

Contribution

It provides the first detailed mapping of the underlying Fermi surface in Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$, highlighting the effects of Ca substitution on electronic properties.

Findings

Quasi-one-dimensional Fermi surface observed

Charge density wave gap detected in x=0

Absence of quasi-particle peak at x=11

Abstract

We have performed an angle-resolved photoemission study of the two-leg ladder system Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$ with $x$= 0 and 11. "Underlying Fermi surfaces" determined from low energy spectral weight mapping indicates the quasi-one dimensional nature of the electronic structure. Energy gap caused by the charge density wave has been observed for $x$=0 and the gap tends to close with Ca substitution. The absence of a quasi-particle peak even in $x$=11 is in contrast to the two-dimensional high-$T_c$ cuprates, implying strong carrier localization related to the hole crystalization.