July 17, 2025 Dataset Open Access

Titvinidze, Irakli; Stobbe, Julian; Leusch, Marvin; Rohringer, Georg

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{"DOI":"10.25592/uhhfdm.17952","abstract":"<p>In this paper, we investigate the impact of nonlocal correlations on charge fluctuations in the<br>\ntwo-dimensional single-band Hubbard model close to the Mott metal-to-insulator transition, em-<br>\nploying the ladder dynamical vertex approximation. At half-filling and for interaction strengths and<br>\ntemperatures where the system is in the Mott insulating phase, charge fluctuations are strongly<br>\nsuppressed. Under these conditions, dynamical mean-field theory (DMFT) calculations predict a<br>\nstrong enhancement of the charge susceptibility at small (electron or hole) doping. However, these<br>\nDMFT results include only the effects of purely local correlations despite the importance of nonlo-<br>\ncal correlations in two-dimensional systems. We have, hence, carried out ladder dynamical vertex<br>\napproximation (lD&Gamma;A) simulations which allow for the inclusion of such nonlocal correlation effects<br>\nwhile retaining the local ones of DMFT. Our lD&Gamma;A numerical data show that close to half-filling<br>\nthe large uniform charge susceptibility of DMFT is strongly suppressed by nonlocal fluctuations but<br>\ngradually increases with (electron) doping. At a certain doping value, charge fluctuations eventually<br>\nbecome larger in lD&Gamma;A with respect to DMFT indicating that the absence of nonlocal correlations<br>\nunderestimates the mobility of the charge carriers in this parameter regime. This metallization effect<br>\nis also reflected in an enhancement of the lD&Gamma;A kinetic and potential energies and a corresponding<br>\nreduction of the (absolute value of the) lD&Gamma;A Matsubara self-energy with respect to DMFT.</p>","author":[{"family":"Titvinidze, Irakli"},{"family":"Stobbe, Julian"},{"family":"Leusch, Marvin"},{"family":"Rohringer, Georg"}],"id":"17952","issued":{"date-parts":[[2025,7,17]]},"language":"eng","title":"Suppression of the charge fluctuations by nonlocal correlations close to the Mott transition","type":"dataset"}