| Description |
Understanding and modeling correlated electronic spectra has remained a constant theme of research for decades. We have relatively better modeling capabilities for systems residing either in the weakly or strongly correlated regimes. However, the intermediate coupling regime (where the Coulomb interaction is of the order of its bandwidth) poses a challenge since both the Fermi-liquid or dynamical mean-field theories are inadequate here. Over the last few years, we have been working on developing a computational scheme for this problem.[1-3] Our intermediate coupling model is based on materials-specific band structure, from which self-energy correction is computed via a self-consistent approach including full momentum dependent dynamical correlations. In this talk, I will present results for several representative correlated materials including copper-oxide (cuprate) high-Tc superconductors, actinide compounds, and various complex oxides. A universal feature of intermediate coupling scenario is that the self-energy splits the electronic structure into low-energy coherent states (emergent Fermi liquid state), and high-energy localized state (residual Mott state), yielding a coexistence of itinerant (wave-like) and localized (atom-like) states. The resulting electronic fingerprint reveals a universal ‘S’ or `waterfall’ shape in the dispersion, and a peak-dip-hump feature in the density of states. The results suggest a generic route for formulating the correlated electronic states for a larger energy span from which a unified theory of high-Tc superconductivity may emerge.
References
[1] Das, Zhu, Graf, Phys. Rev. Lett. 108, 017001 (2012).
[2] Das, Durakiewicz, Zhou, Joyce, Sarrao, Graf, Phys. Rev. X 2, 041012 (2012).
[3] Das, Markiewicz, Bansil, review submitted to Adv. Phys (2013).
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