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

The overdoped region of the cuprate phase diagram can display a number of unusual features in its electronic transport which seem to be unconnected to the pseudogap which strongly influences the electronic structure in the underdoped regime. Here we show that the clean overdoped single-layer cuprate Tl$_2$Ba$_2$CuO$_{6+\delta}$ displays charge density wave (CDW) order with a remarkably long correlation length $\xi \approx 190$ Å which disappears above $p_\text{CDW} \approx 0.265$. As $p$ is decreased through $p_\text{CDW}$ the Hall number $n_H$ starts to decrease, quantum oscillations disappear and the $T$-linear component in the resistivity becomes stronger. We argue the first two of these phenomena are naturally explained by a Fermi surface reconstruction which accompanies the emergence of the CDW. Our results demonstrate the importance of charge correlations in overdoped cuprates and show that CDWs can occur in cuprates in the absence of the pseudogap.