"Phase Transitions at Zero Temperature: an Organizing Scheme for Correlated Electron Matter?”" by MeiganAronson (TAMU)

Date: 
Thursday, October 13, 2016 - 4:00pm to 5:00pm
Series: 
Physics and Astronomy Colloquium

Thursdays, 4:00-5:00 pm

1-434 Physics and Astronomy (map)
Reception from 3:30-4:00 p.m.
(unless otherwise posted)

Guest Speaker: Meigan Aronson (Texas A&M University)

Talk Title:  “Phase Transitions at Zero Temperature: an Organizing Scheme for Correlated Electron Matter?”

Abstract:

Electronic correlations are responsible for collective ground states in metals such as superconductivity and magnetic order. Still missing is an overall organizational scheme where we can predict as a function of some generic control parameters where these phases will be stable, and where they will compete. In all classes of correlated electron systems, including heavy fermions, cuprates, organic conductors, and transition metal compounds like the iron pnictides, the suppression of magnetic order can lead to unconventional superconductivity or other exotic phases. Unlike classical phase transitions, the critical fluctuations are quantum mechanical, and when coupled to conduction electrons are known to generate unusual metals that are the normal states for these unconventional ground states.

Progress towards understanding these T=0 phase transitions is impeded by the relative lack of suitable experimental hosts, in particular those that form naturally exactly at the quantum critical point without the need for tuning via pressure, composition, or magnetic field. We report here on a new layered metal YFe2Al10, which is poised at the onset of ferromagnetic order. Although measurements of the field and temperature dependencies of the susceptibility and specific heat suggest a relatively conventional set of exponents controlling the development of spatial and temporal correlations, neutron scattering measurements indicate that only the latter shows critical divergencies in our experimental window. It is possible that T=0 order in YFe2Al10 is achieved by a new class of topological phase transition with strong quantum fluctuations, as proposed for two-dimensional planar ferromagnets.

For more information, contact Jay Hauser

 

We thank the following people for their contributions to the wine fund for the post-colloquium reception:
Prof. Dolores Bozovic, Prof. Mike Cornwall, Prof. Bob Cousins, Prof. Andrea Ghez, Prof. Karoly Holczer, Prof. Eric Hudson, Robert Huff, Prof. Alex Kusenko, Prof. Myank Mehta, Prof. John Miao, Prof. Roberto Peccei, Prof. Claudio Pellegrini, Prof. David Saltzberg, Prof. Jean Turner and Prof. Ben Zuckerman.

 

Location: 
1-434 PAB