Signatures of coherent electronic quasiparticles in the paramagnetic Mott insulator
2014 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 90, no 23, 235129- p.Article in journal (Refereed) Published
We study the Mott insulating state of the half-filled paramagnetic Hubbard model within dynamical mean field theory using a recently formulated stochastic and nonperturbative quantum impurity solver. The method is based on calculating the impurity self energy as a sample average over a representative distribution of impurity models solved by exact diagonalization. Due to the natural parallelization of the method, millions of poles are readily generated for the self energy which allows us to work with very small pole-broadening eta. Solutions at small and large eta are qualitatively different; solutions at large eta show featureless Hubbard bands whereas solutions at small eta <= 0.001 (in units of half bare band width) show a band of electronic quasiparticles with very small quasiparticle weight at the inner edge of the Hubbard bands. The validity of the results are supported by agreement within statistical error sigma(QMC) similar to 10(-4) on the imaginary frequency axis with calculations using a continuous time quantum Monte Carlo solver. Nevertheless, convergence with respect to finite size of the stochastic exact diagonalization solver remains to be rigourously established.
Place, publisher, year, edition, pages
2014. Vol. 90, no 23, 235129- p.
IdentifiersURN: urn:nbn:se:uu:diva-241956DOI: 10.1103/PhysRevB.90.235129ISI: 000346614800002OAI: oai:DiVA.org:uu-241956DiVA: diva2:782134