CAREER: Strongly Correlated Spin Liquid in Frustrated Magnets

Johns Hopkins University, Baltimore MD

Investigators

Abstract

This CAREER award supports theoretical research and education on strongly correlated electron systems with a particular focus on spin liquids in geometrically frustrated magnets. Strongly correlated electrons are a challenging frontier of condensed-matter physics. As exemplified by the fractional quantum Hall effect, their low-temperature properties are different from those of Bose and Fermi liquids. Frustrated magnets represent another class of electronic systems with strong correlations. With magnetic order disrupted by competing interactions, the low-temperature state of these magnets is a disordered spin liquid, in which the motion of spins is highly correlated. The nature of the quantum ground state and elementary excitations in two and three-dimensional spin liquids is a long-standing problem. Theoretical characterization of spin liquids in frustrated magnetic systems comprises the research part of the project. Specifically, the PI will (1) obtain a theoretical description of the spin-liquid state and its instabilities observed experimentally in several frustrated magnets; (2) characterize low-temperature properties of idealized models of frustrated magnets, such as the Heisenberg antiferromagnet on the pyrochlore lattice; (3) investigate the occurrence of chaos in classical dynamics of frustrated spins and its consequences on their quantum properties. Integration of numerical simulations into physics courses is the main educational component of this CAREER development plan. The goal is to increase the effectiveness of the learning process by bridging the gap between theoretical contents of a course and relevant experimental situations. To this end, numerical simulations will be made an integral part of homework. By solving a problem and running a simulation as an independent check of the results, the student will observe the interplay of several key theoretical concepts in a realistic physical setting. To ensure easy access and cross-platform compatibility, the simulations will be produced in the form of Java applets. %%% This CAREER award supports theoretical research and education on strongly correlated electron systems with a particular focus on spin liquids in geometrically frustrated magnets. Strongly correlated electrons are a challenging frontier of condensed-matter physics. As exemplified by the fractional quantum Hall effect, their low-temperature properties are different from those of Bose and Fermi liquids. Frustrated magnets represent another class of electronic systems with strong correlations. With magnetic order disrupted by competing interactions, the low-temperature state of these magnets is a disordered spin liquid, in which the motion of spins is highly correlated. The research component of this award seeks to elucidate the nature of spin liquids and study novel phenomena involving spin liquids in several frustrated magnets. Integration of numerical simulations into physics courses is the main educational component of this CAREER development plan. The goal is to increase the effectiveness of the learning process by bridging the gap between theoretical contents of a course and relevant experimental situations. To this end, numerical simulations will be made an integral part of homework. By solving a problem and running a simulation as an independent check of the results, the student will observe the interplay of several key theoretical concepts in a realistic physical setting. To ensure easy access and cross-platform compatibility, the simulations will be produced in the form of Java applets. ***