Liangzi Deng - Quantum Science and Engineering Seminar

From High Pressure to Ambient: Stabilizing Quantum States Born Under Extreme Conditions

Liangzi Deng | University of Houston

Pressure is a powerful thermodynamic knob for discovering emergent quantum states from record-high-temperature superconductivity to intertwined electronic orders and novel topological and magnetic phases. Our recent work shows that pressure can break the conventional Tc–pressure relationship in superconductors, further enhancing Tc, and can significantly expand the temperature–magnetic field phase space accessible to skyrmion states. However, these states typically emerge only under high pressure, conditions that severely limit both characterization and practical use. To address this, we developed the pressure-quench protocol (PQP), a non-equilibrium approach that kinetically stabilizes pressure-induced or pressure-enhanced quantum metastable states at ambient pressure. By systematically tuning quench pressure, quench temperature, and quench rate, PQP lets us probe the microscopic mechanisms — structural and electronic phase transitions, defect and disorder formation, interfacial effects — that allow favorable high-pressure phases to survive once pressure is released. Conceptually, PQP forms a closed loop: ambient pressure -> high pressure -> ambient pressure, opening a path to studying quantum states that were previously accessible only under extreme conditions. I will discuss several material systems where PQP has succeeded, including the stabilization of a record ambient-pressure superconducting Tc of up to 151 K in HgBa2Ca2Cu3O8+δ.

Liangzi Deng is an Assistant Professor in Physics and the Texas Center for Superconductivity at the University of Houston, where he earned his Ph.D. under Ching-Wu Chu. He studies superconductivity, magnetism, and topological properties under pressure, and is a recipient of the MRS Early Career Researcher Award and TAMEST 2026 Protégé honor.

Host: Shuolong Yang