Two‐Dimensional Mott Insulators in SrVO3 Ultrathin Films

• Published in: Advanced materials interfaces Vol. 1; no. 7
• Main Authors: Gu, Man, Wolf, Stuart A., Lu, Jiwei
• Format: Journal Article
• Language: English
• Published: 01.10.2014
• Subjects: electrical transport; metal‐insulator transition; Mott insulator; SrVO3; thin film
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.201300126

Strongly correlated oxides that undergo a metal‐insulator transition (MIT) are a subject of great current interest for their potential application to future electronics as switches and sensors. Recent advances in thin film technology have opened up new avenues to tailor MIT for novel devices beyond conventional CMOS scaling. Here, dimensional‐crossover‐driven MITs are demonstrated in high‐quality epitaxial SrVO3 (SVO) thin films grown by a pulsed electron‐beam deposition technique. Thick SVO films (∼25 nm) exhibit metallic behavior with the electrical resistivity following the T2 law corresponding to a Fermi liquid system. A temperature driven MIT is induced in SVO ultrathin films with thicknesses below 6.5 nm. The transition temperature TMIT is at 50 K for the 6.5 nm film, 120 K for the 5.7 nm film and 205 K for the 3 nm film. The emergence of the observed MIT can be attributed to the dimensional crossover from a three‐dimensional metal to a two‐dimensional Mott insulator, as the resulting reduction in the effective bandwidth W opens a band gap at the Fermi level. The magneto‐transport study of the SVO ultrathin films also confirm the observed MIT is due to the electron‐electron interactions other than disorder‐induced localization. A metal‐insulator transition (MIT) induced in high‐quality epitaxial SrVO3 (SVO) ultrathin films with thicknesses less than 6.5 nm (ca.17 monolayers) is demonstrated. It is shown that the emergence of the MIT is due to dimensional cross‐over from a three‐dimensional metal to a two‐dimensional Mott insulator, and any competing effects like Anderson localization are small and do not significantly contribute to the transport. Here, the first transport study to show this crossover is presented, and earlier photoemission results are confirmed.