Quantum Criticality and Strong Correlations in Low-dimensional Metals
Nov 19, 2014
3:30PM to 4:30PM
Date(s) - 19/11/2014
3:30 pm - 4:30 pm
Title: Quantum Criticality and Strong Correlations in Low-dimensional Metals
Speaker: Dr. Meigan Aronson
Institute: Stony Brook University
Location: ABB 102
T=0 phase transitions or `Quantum Critical Pointsâ?? are found in virtually every class of correlated electron system, including cuprates, heavy fermions, Fe-based pnictides, and organic conductors, and their presence fundamentally changes the properties of the underlying metal from which these ordered phases emerge. The associated critical modes can lead to the nucleation of novel phases provide pairing for unconventional superconductors, and can lead to the destruction of the metallic state via the localization of electrons. There are two approaches to creating QCPs in metals. In the first, an ordered phase, most often magnetic, is suppressed by geometric frustration, dimerization, or simply by low dimensionality, all of which strengthen quantum fluctuations at the expense of order. Alternatively, increased hybridization of the moment bearing electrons with conduction electrons diminishes correlations and leads to conventional metallic states.
In this talk I will focus on the role of dimensionality in stabilizing QCPs. Our high precision measurements of the magnetic susceptibility, specific heat, and electrical resistivity in the layered compound YFe2Al10 demonstrate robust field-temperature scaling, evidence that this system is naturally poised without tuning on the verge of ferromagnetic order that occurs exactly at T = 0, where magnetic fields drive the system away from this quantum critical point and restore normal metallic behavior. The critical exponents deduced from this analysis establish the validity of hyperscaling, implying that YFe2Al10 is the first confirmed member of a new universality class.