title: Colossal positive magnetoresistance in surface-passivated oxygen-deficient strontium titanite.
abstract: Modulation of resistance by an external magnetic field, i.e. magnetoresistance effect, has been a long-lived theme of research due to both fundamental science and device applications. Here we report colossal positive magnetoresistance (CPMR) (>30,000% at a temperature of 2 K and a magnetic field of 9 T) discovered in degenerate semiconducting strontium titanite (SrTiO3) single crystals capped with ultrathin SrTiO3/LaAlO3 bilayers. The low-pressure high-temperature homoepitaxial growth of several unit cells of SrTiO3 introduces oxygen vacancies and high-mobility carriers in the bulk SrTiO3, and the three-unit-cell LaAlO3 capping layer passivates the surface and improves carrier mobility by suppressing surface-defect-related scattering. The coexistence of multiple types of carriers and inhomogeneous transport lead to the emergence of CPMR. This unit-cell-level surface engineering approach is promising to be generalized to others oxides, and to realize devices with high-mobility carriers and interesting magnetoelectronic properties.
authors.affiliation: 1] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore [2] Laboratoire CRISMAT, ENSICAEN, CNRS UMR 6508, 6 Boulevard Maréchal Juin, F-14050 Caen Cedex, France.
authors.forename: Adrian
authors.initials: A
authors.lastname: David
authors.affiliation: School of Physics, National Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, P. R. China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore.
authors.forename: Ping
authors.initials: P
authors.lastname: Yang
authors.affiliation: Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, P. R. China.
authors.forename: Xingyu
authors.initials: X
authors.lastname: Gao
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Weinan
authors.initials: W
authors.lastname: Lin
authors.affiliation: Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana-Champaign 1304 W Green Street Urbana, IL 61801, USA.
authors.forename: Amish B
authors.initials: AB
authors.lastname: Shah
authors.affiliation: Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana-Champaign 1304 W Green Street Urbana, IL 61801, USA.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zuo
authors.affiliation: Laboratoire CRISMAT, ENSICAEN, CNRS UMR 6508, 6 Boulevard Maréchal Juin, F-14050 Caen Cedex, France.
authors.forename: Wilfrid
authors.initials: W
authors.lastname: Prellier
authors.affiliation: Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Tom
authors.initials: T
authors.lastname: Wu