Electrical properties and subband occupancy at the ( La , Sr ) ( Al , Ta ) O 3 / SrTiO 3 interface

K. Han,1,2 Z. Huang,1,2,* S. W. Zeng,1,2 M. Yang,3 C. J. Li,4 W. X. Zhou,1,2 X. Renshaw Wang,5 T. Venkatesan,1,2,4,6,7 J. M. D. Coey,1,8 M. Goiran,3 W. Escoffier,3 and Ariando1,2,6,† 1NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore 2Department of Physics, National University of Singapore, Singapore 117542, Singapore 3Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), CNRS-UGA-UPS-INSA, 143 Avenue de Rangueil, 31400 Toulouse, France 4Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore 5School of Physical and Mathematical Sciences & School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore 6National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), 28 Medical Drive, Singapore 117456, Singapore 7Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore 8School of Physics and CRANN, Trinity College, Dublin 2, Ireland (Received 20 February 2017; published 19 June 2017)