Speaker
Description
Despite decades of intense research, the microscopic mechanism of high-temperature superconductivity in the cuprates remains unresolved. A central obstacle is the limited tunability of these materials: unlike many two-dimensional systems, the charge carrier density in cuprate superconductors is fixed during synthesis, making it difficult to continuously access and manipulate competing electronic phases using conventional gating approaches.
In this talk, I show that substrate engineering provides a powerful alternative route to control the electronic ground state of cuprates, enabling access to new phases and reshaping their interplay with superconductivity. Focusing on nm thick YBa₂Cu₃O₇₋ₓ films, I demonstrate that substrates with a nanofaceted surface morphology, formed by high-temperature surface reconstruction induce electronic nematicity and a unidirectional charge-density wave, stabilizing a novel ground state distinct from that of thicker films and bulk crystals.
Remarkably, these interfacial effects lead to a strong enhancement of superconductivity: the onset temperature increases by more than 20 K, and the upper critical magnetic field is enhanced by more than 50 T at fixed doping. Together, these results establish substrate engineering as a powerful strategy for tuning quantum phases in cuprates and for designing high-performance superconducting materials.