Electrostatic Tuning of the Hole Density in NdBa₂Cu₃O_7-δ Films and its Effect on the Hall Response

We have used the ferroelectric field effect in heterostructures based on superconducting NdBa2Cu3O7-delta and ferroelectric Pb(Zr0.2Ti0.8)O-3 to electrostatically modulate in a reversible and nonvolatile fashion the hole carrier density of the superconducting layer. Reversing the ferroelectric polarization induces a constant relative change in the resistivity and Hall constant of 9% and 6%, respectively, at all temperatures above the superconducting transition. The cotangent of the Hall angle displays a T-2 dependence with a slope that increases as the carrier density is reduced