Charge density waves and Fermi-surface reconstruction in the clean overdoped cuprate superconductor Tl2Ba2CuO6+x

TL;DR

This study reveals charge density wave order and Fermi surface reconstruction in overdoped Tl2Ba2CuO6+x, linking these phenomena to changes in electronic structure and high-temperature superconductivity in cuprates.

Contribution

It provides direct evidence of CDW order with long-range correlations in overdoped cuprates and connects this to Fermi surface changes near a critical doping level.

Findings

CDW order appears below p_CDW ~ 0.265 in Tl2201

Fermi surface reconstruction correlates with CDW emergence

CDW correlations are crucial for understanding overdoped cuprate electronic properties

Abstract

Hall effect and quantum oscillation measurements on high temperature cuprate superconductors show that underdoped compositions have a small Fermi surface pocket whereas when heavily overdoped, the pocket increases dramatically in size. The origin of this change in electronic structure has been unclear, but may be related to the high temperature superconductivity. Here we show that the clean overdoped single-layer cuprate Tl2Ba2CuO6+x (Tl2201) displays CDW order with a remarkably long correlation length $\xi \approx 200$ \r{A} which disappears above a hole concentration p_CDW ~ 0.265. We show that the evolution of the electronic properties of Tl2201 as the doping is lowered may be explained by a Fermi surface reconstruction which accompanies the emergence of the CDW below p_CDW. Our results demonstrate importance of CDW correlations in understanding the electronic properties of overdoped cuprates.