New insights into correlated electron materials from new computational methods

Andrew J. Millis, Columbia University, DMR 0705847

The study of quantum many-body problems has been hampered by a lack of reliable numerical methods. The Millis group has developed the cluster dynamical mean field method to the point where wide regimes of parameter space can be surveyed and the accuracy of different cluster schemes can be compared. We found a previously unknown ‘sector-selective’ route to the correlation-driven metal-insulator transition and showed that this accounts for many of the properties of high-Tc superconductors, including the variation of electron scattering around the fermi surface and the ‘pseudogap’, a suppression of the many-body density of states in `hole-doped’ but not `electron-doped’ materials.

Phys. Rev. B80 045120 (2009)Phys. Rev. B80, 245102 (2009)arXiv:1007:2592 (Phys Rev B in press)

2,4,8,16 site clusters we have studied

Blue: pseudogap; red, Mott gap.

Theory Conductivity Experiment

New insights into correlated electron materials from new computational methods

Andrew J. Millis, Columbia University, DMR 0705847

Broader Impacts:

•Organizer, Feb 2010 `Materials by Design’, Kavli Institute for Theoretical Physics conference

•Lecturer, US Summer School on Condensed Matter and Materials Physics, July 2010

•Organizer, Les Houches Summer School on Nonequilibrium Quantum Field Theory (to be held in 2012)

•Organizer, DMP Focus Session on Oxide Interfaces