A microscopic view on the Mott transition in chromium-doped V2O3

• Published in: Nature communications Vol. 1; no. 1; p. 105
• Main Authors: Lupi, S., Baldassarre, L., Mansart, B., Perucchi, A., Barinov, A., Dudin, P., Papalazarou, E., Rodolakis, F., Rueff, J. -P., Itié, J. -P., Ravy, S., Nicoletti, D., Postorino, P., Hansmann, P., Parragh, N., Toschi, A., Saha-Dasgupta, T., Andersen, O. K., Sangiovanni, G., Held, K., Marsi, M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.11.2010; Nature Publishing Group
• Subjects: 639/301/119/997; 639/638/263/914; 639/638/440/951; 639/638/563/758; Condensed Matter; Humanities and Social Sciences; multidisciplinary; Physics; Science; Science (multidisciplinary); Strongly Correlated Electrons
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms1109

V 2 O 3 is the prototype system for the Mott transition, one of the most fundamental phenomena of electronic correlation. Temperature, doping or pressure induce a metal-to-insulator transition (MIT) between a paramagnetic metal (PM) and a paramagnetic insulator. This or related MITs have a high technological potential, among others, for intelligent windows and field effect transistors. However the spatial scale on which such transitions develop is not known in spite of their importance for research and applications. Here we unveil for the first time the MIT in Cr-doped V 2 O 3 with submicron lateral resolution: with decreasing temperature, microscopic domains become metallic and coexist with an insulating background. This explains why the associated PM phase is actually a poor metal. The phase separation can be associated with a thermodynamic instability near the transition. This instability is reduced by pressure, that promotes a genuine Mott transition to an eventually homogeneous metallic state. The spatial scale over which metal–insulator transitions happen is not known, despite the importance of this phenomenon in basic and applied research. The authors show that in chromium-doped V 2 O 3 , with decreasing temperature, microscopic metallic domains coexist with an insulating background.