LaTiO3/KTaO3 interfaces: A new two-dimensional electron gas system
K. Zou,
Sohrab Ismail-Beigi,
Kim Kisslinger,
Xuan Shen,
Dong Su,
F. J. Walker,
C. H. Ahn
Affiliations
K. Zou
Department of Applied Physics and Center for Research on Interface Structures and Phenomena (CRISP), Yale University, New Haven, Connecticut 06520, USA
Sohrab Ismail-Beigi
Department of Applied Physics and Center for Research on Interface Structures and Phenomena (CRISP), Yale University, New Haven, Connecticut 06520, USA
Kim Kisslinger
Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973, USA
Xuan Shen
Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973, USA
Dong Su
Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973, USA
F. J. Walker
Department of Applied Physics and Center for Research on Interface Structures and Phenomena (CRISP), Yale University, New Haven, Connecticut 06520, USA
C. H. Ahn
Department of Applied Physics and Center for Research on Interface Structures and Phenomena (CRISP), Yale University, New Haven, Connecticut 06520, USA
We report a new 2D electron gas (2DEG) system at the interface between a Mott insulator, LaTiO3, and a band insulator, KTaO3. For LaTiO3/KTaO3 interfaces, we observe metallic conduction from 2 K to 300 K. One serious technological limitation of SrTiO3-based conducting oxide interfaces for electronics applications is the relatively low carrier mobility (0.5-10 cm2/V s) of SrTiO3 at room temperature. By using KTaO3, we achieve mobilities in LaTiO3/KTaO3 interfaces as high as 21 cm2/V s at room temperature, over a factor of 3 higher than observed in doped bulk SrTiO3. By density functional theory, we attribute the higher mobility in KTaO3 2DEGs to the smaller effective mass for electrons in KTaO3.
