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Dimensionality Control of Electronic Phase Transitions in Nickel-Oxide Superlattices
- Boris, A.V., Matiks, Y., Benckiser, E., Frano, A., Popovich, P., Hinkov, V., Wochner, P., Castro-Colin, M., Detemple, E., Malik, V.K., Bernhard, C., Prokscha, T., Suter, A., Salman, Z., Morenzoni, E., Cristiani, G., Habermeier, H.-U., Keimer, B.
- Science 2011 v.332 no.6032 pp. 937-940
- electrons, ferrimagnetic materials, lanthanum, phase transition, temperature
- The competition between collective quantum phases in materials with strongly correlated electrons depends sensitively on the dimensionality of the electron system, which is difficult to control by standard solid-state chemistry. We have fabricated superlattices of the paramagnetic metal lanthanum nickelate (LaNiO₃) and the wide-gap insulator lanthanum aluminate (LaAlO₃) with atomically precise layer sequences. We used optical ellipsometry and low-energy muon spin rotation to show that superlattices with LaNiO₃ as thin as two unit cells undergo a sequence of collective metal-insulator and antiferromagnetic transitions as a function of decreasing temperature, whereas samples with thicker LaNiO₃ layers remain metallic and paramagnetic at all temperatures. Metal-oxide superlattices thus allow control of the dimensionality and collective phase behavior of correlated-electron systems.