CAREER: Emergent Quantum Spin-Liquid in Yb-Pyrochlores and Yb-Spinels

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

Technical Abstract Amongst the celebrated exotic phases of condensed matter, of particular recent interest are the quantum spin liquids (QSLs). It is widely believed that extreme quantum entanglement and geometrical frustration lead to QSLs' defining properties: strong spin correlations, the absence of static magnetic moments, and unbroken crystalline symmetry. Despite the intensive studies on QSLs, the response of the QSL state to various perturbations, such as chemical pressure, site disorder, and extra magnetic interactions, has not been thoroughly studied. Moreover, one main obstacle for QSL studies is the shortage of the examples. This award supports an experimental approach for studying the correlations between the local structural variations of the Yb3+ ions and both the perturbation effects on the QSL state in different Yb-pyrochlores and the exotic magnetism of various Yb-spinels. In both cases the geometrically frustrated corner-shared tetrahedral Yb3+-network strongly influences their magnetic properties. The investigator will synthesize, and grow crystals of new Yb-pyrochlores and new Yb-spinels and study two important physical aspects: (i) the nature of their magnetic ground states by using AC susceptibility measurements and neutron scattering; (ii) the local structural variations of the Yb3+ magnetic ions by using the pair distribution function technique. The program will train two graduate students; and aims to attract undergraduate and high school students, particularly minority students, to motivate and expose to the real world of science and technology. This will be acheived in collaboration with the Educational Advanced Program (EAP) and the Tennessee Louis Stokes Alliance for Minority Participation (TLSAMP) program at the University of Tennessee. The investigator will also provide crystals and offer services for training students on crystal growth and crystal processing to a broader scientific community. Non-Technical Abstract The understandings of the physical properties of quantum matters have been at the forefront of modern condensed matter physics research. One recent example is quantum spin liquids (QSLs): a unique state with strong spin correlations but without static magnetic order. The geometrical arrangements of the magnetic atoms prevent them to direct their magnetic moment, the materials are magnetically frustrated. The exotic properties of QSLs appear only at extremely low temperatures, and are expected to be sensitive to various perturbations. Moreover, one main obstacle for QSL studies is the shortage of examples. This program will explore new QSL materials and study the perturbation effects on them. Single crystals of the QSL candidates will be grown in the investigator's laboratory and then will be studied by various methods under low temperatures and high magnetic fields. The program will train two graduate students; and aims to attract undergraduate and high school students, particularly minority students, to motivate and expose them to the real world of science and technology. This will be acheived in collaboration with the Educational Advanced Program (EAP) and the Tennessee Louis Stokes Alliance for Minority Participation (TLSAMP) program at the University of Tennessee. The investigator will also provide crystals and offer services for training students on crystal growth and crystal processing to a broader scientific community.