EAGER: Ultrasound Studies in High Fields and High Strain of the Normal State in Unconventional Odd Parity Superconductors

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

Non-technical Abstract New materials are driving advances that will revolutionize many areas ranging from standard to quantum computing. One type of material of particular interest are unconventional superconductors. These materials, which are often described as strongly correlated electronic systems, have several novel properties in both their normal and superconducting state that make them a desirable platform for new applications. Such correlations can make the electrons exhibit novel effects such as chirality i.e. handedness and nematicity or orientational order. These novel electronic effects can be exploited in new quantum technologies for computing and secure communication. Mastering the control of different quantum phases is an integral part in the development of such high pay-off new technologies. This research will use velocity of sound measurements in high magnetic fields and with the application of uniaxial pressure to locate the various magnetic phases and study how they evolve. The project will also support the involvement of students in research as well as outreach activities to local schools and museums. Technical Abstract This award is for experimental work in very high magnetic fields and high pressures, applied uniaxially, on the heavy electron system UPt3. This is a unique metal which exhibits multiple phases in its superconducting (SC) as well in the normal magnetic states. In UPt3 a minute trigonal distortion, i.e. a departure from its nominal hexagonal crystal symmetry is known to exist. Such symmetry breaking effects are quite general in many families of strongly correlated electronic systems (SCES). Multiple states such as charge (CDW) and spin (SDW) density waves, unconventional superconductivity and novel magnetic phases can coexist in SCES and precisely controlled experiments are needed to tease out the various physical interactions. Through a combined application of high magnetic fields and large uniaxial stress the PI proposes to delicately tune the broken crystal symmetry in UPt3. Such a conjoint application of two very large external fields, magnetic and pressure, has hitherto never been employed and hence the proposed work is risky. The different magnetic phases and how they evolve under simultaneous application of high magnetic fields and high pressure will be studied by measuring the velocity of ultrasound passing through crystals of UPt3. Sound velocity is a very sensitive measure of how electrons in the different magnetic and SC phases behave. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.