Effect of pressure on the pseudogap and charge-density-wave phases of the cuprate La${}_{1.6-x}$Nd${}_{0.4}$Sr${}_x$CuO${}_4$ probed by thermopower measurements

Abstract

We report thermopower measurements under hydrostatic pressure on the cuprate superconductor La${}_{1.6-x}$Nd${}_{0.4}$Sr${}_x$CuO${}_4$ (Nd-LSCO), at low-temperature in the normal state accessed by suppressing superconductivity with a magnetic field up to $H=31$ T. Using a newly developed AC thermopower measurement technique suitable for high pressure and high field, we track the pressure evolution of the Seebeck coefficient $S$. At ambient pressure and low temperature, $S/T$ was recently found to suddenly increase in Nd-LSCO at the pseudogap critical doping $p^{\star }=0.23$, consistent with a drop in carrier density $n$ from $n=1+p$ above $p^{\star }$ to $n=p$ below. Under a pressure of 2.0 GPa, we observe that this jump in $S/T$ is suppressed. This confirms a previous pressure study based on electrical resistivity and Hall effect which found $d{p}^{\star }/dP\simeq -0.01$ holes/GPa, thereby reinforcing the interpretation that this effect is driven by the pressure-induced shift of the van Hove point. It implies that the pseudogap only exists when the Fermi surface is hole-like, which puts strong constraints on theories of the pseudogap phase. We also report thermopower measurements on Nd-LSCO and La${}_{1.8-x}$Eu${}_{0.2}$Sr${}_x$CuO${}_4$ in the charge density-wave phase near $p\sim 1/8$, which reveals a weakening of this phase under pressure.

9 pages, 5 figures

References in corpus (9)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor
• Two-Dimensional Superconducting Fluctuations in Stripe-Ordered La(1.875)Ba(0.125)CuO(4)
• On the thermoelectricity of correlated electrons in the zero-temperature limit
• Pseudogap phase of cuprate superconductors confined by Fermi surface topology
• Evidence for a small hole pocket in the Fermi surface of underdoped YBa2Cu3Oy
• Negative Hall coefficients of heavily overdoped La2-xSrxCuO4
• Rapid Suppression of the Charge Density Wave in YBa${}_2$Cu${}_3$O${}_{6.6}$ under Hydrostatic Pressure
• Thermopower across the phase diagram of the cuprate La${}_{1.6-x}$Nd${}_{0.4}$Sr${}_x$CuO${}_4$ : signatures of the pseudogap and charge-density-wave phases

Cited by in corpus (2)

• Seebeck coefficient in a cuprate superconductor: particle-hole asymmetry in the strange metal phase and Fermi surface transformation in the pseudogap phase
• Magneto-Seebeck effect in bismuth