LASSP & AEP Seminar: Johnpierre Paglione (Maryland)

Key Issues in Understanding the Superconductivity of UTe2

The spin-triplet superconductor UTe2 has recently emerged as a rich system that incorporates aspects of unconventional superconductivity, heavy-electron physics and non-trivial topologies. Superconductivity in UTe2 is characterized by enormous upper critical fields that exceed the paramagnetic limit and re-enter in ultra-high fields, nodal quasiparticle excitations, chiral in-gap surface states, and multiple distinct superconducting phases that span regimes of temperature, magnetic field and applied pressure. Superconductivity emerges from a renormalized electronic structure of hybridized f-electrons which give rise to archetypal heavy fermion features such as an enhanced quasiparticle heat capacity and hybridization gap, yet key questions about the nature of magnetism, electronic structure, order instabilities and sample dependence remain. In particular, recent advances in crystal quality have been achieved by varying synthesis methods – including variations in techniques, composition and even temperature ranges used for growth – to enable enhancements in conductivity, transition temperature and ability to measure quantum oscillations. This talk will review the evolution of sample variations and resultant physical properties of UTe2 that shed light on the nature of superconductivity in different parameter regimes of temperature, pressure and magnetic fields.

Bio:
Johnpierre Paglione has seeded a world-class effort on quantum materials research at the University of Maryland, leading the collaborations of several faculty that have brought Maryland to the forefront of research on superconductivity, topological materials and strongly correlated systems. Having contributed to several fields of experimental condensed matter research through both single-crystal synthesis and ultra-low temperature transport, thermodynamic and spectroscopic exploration of novel phenomena, Paglione’s research is a blend of materials exploration and elucidation of quantum phenomena. As director of the Maryland Quantum Materials Center, with a membership of over 100 personnel, a state-of-the-art materials synthesis facility and an extensive measurement suite, Paglione commits QMC resources to hosting the annual Fundamentals of Quantum Materials Winter School, a successful hands-on training program and basis for this work. Paglione is the recipient of a National Science Foundation CAREER Award and an Early Career Award from the Department of Energy, is a Materials Synthesis Fellow in the EPiQS program of the Gordon and Betty Moore Foundation and a Fellow of the Quantum Materials Program of the Canadian Institute for Advanced Research. Prof. Paglione earned his Ph.D. from the University of Toronto.