Disorder and Emergence of Inhomogeneous Phases in Strongly Correlated Electron Systems

Peter J. Hirschfeld, University of Florida, DMR 1005625

Correlated electron systems near the metal-insulator transition are often unstable to a variety of inhomogneous phases like charge and spin density waves (SDW), and in some circumstances these can coexist with high temperature superconductivity (SC). A fingerprint of this coexistence are the unique spin excitations in such a system (panel a), which were calculated for a SDW/SC system, and should be observable by neutron scattering.

Scanning tunneling spectroscopy (STS) shows that in some cuprate high temperature superconductors the gap varies strongly from place to place. This can be due to the effect of an impurity on the “glue” which binds electrons into pairs, as shown in our calculations (panel b).

(a)

Spin excitations in a transverse susceptibility for spin density wave coexisting with d-wave superconductor, indicating spin waves, spinresonance, & particle hole excitations (aXv:1207.3834).

Modulation of nearest neighbor pairing interactionnear strong impurity in the Hubbard model (aXv:1206.0888).

Disorder and Emergence of Inhomogeneous Phases in Strongly Correlated Electron Systems

Peter J. Hirschfeld, University of Florida, DMR 1005625

Outreach efforts were primarily devoted to public education regarding superconductivity. The PI gave general colloquia and public lectures, particularly in association with the 100th anniversary of the discovery of superconductivity in 2011, including the Niels Bohr Lecture (left). The Cargese workshop “Multiorb 2011” (Aug. 2011) co-organized by the PI, was an official part of the French celebration of this anniversary, and covered inhomogeneous states in multiorbital correlated electron systems.

Wenya Wang, a grad student in PI’s group, was the recipient of a U. Florida summer fellowship to do research at U. Bochum in Germany.

Grad student Wenya Wang (US citizen)