Competitive Structural and Electronic States Under Pressure

By tuning interatomic interactions, pressure drives materials toward structural and electronic instabilities - regimes where novel phases such as superconductivity, charge ordering, and magnetism can emerge, compete, or coexist. These transitional regions often lie near quantum critical points, where fluctuations persist down to zero temperature and give rise to rich, unconventional behavior. Pressure provides a powerful tool for probing these instabilities and uncovering the fundamental physics that governs quantum materials.

In this talk, I will highlight recent advancements in our understanding of competing states under high pressure, with a focus on pressure-induced structural and electronic transitions. Key examples include the interplay between charge-density-wave (CDW) order and superconductivity in the two dimensional material BaSbTe2.1S0.9, and the modification of magnetic ground states in the unconventional colossal magnetoresistance (CMR) system EuCd2P2. I will also present our studies on quantum lattice effects in lithium, where strong nuclear zero-point motion leads to isotope dependent structural transitions and superconducting behavior. These efforts have helped resolve the longstanding mystery of lithium’s ground state and have enabled us to experimentally map its Fermi surface and pressure-dependent electronic structure in isotopically pure samples.

Together, these studies demonstrate the power of high-pressure research in accessing quantum critical phenomena, disentangling competing orders, and guiding the discovery of materials with emergent and tunable functionalities.

Speaker: Shanti Deemyad, University of Utah