Effect of chromium doping on the correlated electronic structure ofV2O3

Abstract

The archetypical strongly correlated Mott-phenomena compound V2O3 is known to show a paramagnetic metal-insulator transition driven by doping with chromium atoms and/or (negative) pressure. Via charge self-consistent density-functional theory+dynamical mean-field theory calculations we demonstrate that these two routes cannot be understood as equivalent. To this end, the explicit description of Cr-doped V2O3 by means of supercell calculations and the virtual crystal approximation is performed. Already the sole introduction of chromium's additional electron to the system is shown to modify the overall correlated electronic structure substantially. Correlation-induced charge transfers between Cr and the remaining V ions occur and the transition-metal orbital polarization is increased by the electron doping, in close agreement with experimental findings.

Realistic many-body approaches to materials with strong nonlocal correlations

“…Fig. 5c), giving rise to the measured orbital polarization [73]. Note that is has indeed been shown [95], that applied pressure on insulating Cr-doped V 2 O 3 renders the system metallic without substantial changes in the orbital polarization.…”

“…Besides stoichiometric compounds with larger primitive cells, real-space DFT + DMFT is suited to investigate realistic defect physics in correlated materials, e.g., naturally occuring via doping or through intrinsic (point) defects. The research field of realistic defect-based many-body physics, albeit a pressing problem in many persistent quantum-materials challenges, is only about to receive more attention in recent years [72,73]. Let us note that of course also the standard cluster extensions to DMFT (see e.g., [25] for a review) can be allied with DFT in similar manners.…”

“…Experimentally, in essence, Cr-doping drives V 2 O 3 insulating at constant temperature, accompanied by a subtle lattice expansion [81] as well as orbital polarization towards e g [82]. First-principles DFT [83][84][85][86][87] and DFT + DMFT [62,67,73,[88][89][90][91][92] studies approached the problem. Originally, the focus of most of the theoretical works is on the "proper averaged" electronic properties, i.e., leaving the very details of the (electron-)lattice degrees of freedom and the doping/defect physics aside.…”

“…Recently original [67] and follow-up charge self-consistent DFT + DMFT [73,91,92] suggests some modifications to this picturing. The correlation-enhanced orbital polarization in stoichiometric V 2 O 3 (with or without expanded lattice) is predicted to be much weaker.…”

Электронно-Микроскопическое Исследование Кинетики Слоевой И Островковой Кристаллизации Аморфных Пленок v-=sub=-2-=/Sub=-O-=sub=-3-=/Sub=-, Осажденных Импульсным Лазерным Напылением

“…Проводимые в настоящее время многочисленные тео-ретические и экспериментальные исследования струк-туры и свойств полуторной окиси ванадия (V 2 O 3 ) обусловлены наличием фазовых переходов типа ме-талл−изолятор и металл−полупроводник, зависящих от температуры, давления и концентрации легирующих примесей [1][2][3]. Так, выше 150 K проводимость V 2 O 3 возрастает на 7 порядков вследствие перехода изолятор (антиферромагнетик) с моноклинной структурой -ме-талл с ромбоэдрической структурой.…”