Switchable Induced Polarization in LaAlO3/SrTiO3 Heterostructures

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Nano Letters

DOI:https://doi.org/10.1021/nl3001088· OSTI ID:1039246

Bark, C ^[1]; Sharma, P. ^[2]; Wang, Y. ^[2]; Baek, Seung Hyub ^[1]; Lee, S. ^[1]; Ryu, S. ^[1]; Folkman, C H ^[3]; Paudel, Tula R ^[4]; Kumar, Amit ^[4]; Kalinin, Sergei V ^[4]; Sokolov, A. ^[2]; Tsymbal, E Y ^[5]; Rzchowski, M ^[3]; Gruverman, Alexei ^[4]; Eom, Professor Chang-Beom ^[1]

---

1. University of Wisconsin, Madison
2. University of Nebraska
3. University of Wisconsin
4. ORNL
5. University of Nebraska, Lincoln

Demonstration of a tunable conductivity of the LaAlO3/SrTiO3 interfaces drew significant attention to the development of oxide electronic structures where electronic confinement can be reduced to the nanometer range. While the mechanisms for the conductivity modulation are quite different and include metal insulator phase transition and surface charge writing, generally it is implied that this effect is a result of electrical modification of the LaAlO3 surface (either due to electrochemical dissociation of surface adsorbates or free charge deposition) leading to the change in the twodimensional electron gas (2DEG) density at the LaAlO3/SrTiO3 (LAO/STO) interface. In this paper, using piezoresponse force microscopy we demonstrate a switchable electromechanical response of the LAO overlayer, which we attribute to the motion of oxygen vacancies through the LAO layer thickness. These electrically induced reversible changes in bulk stoichiometry of the LAO layer are a signature of a possible additional mechanism for nanoscale oxide 2DEG control on LAO/STO interfaces.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1039246
• Journal Information: Nano Letters, Vol. 12, Issue 4; ISSN 1530-6984
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CONFINEMENT
DEPOSITION
DISSOCIATION
ELECTRON GAS
ELECTRONIC STRUCTURE
LAOS
MICROSCOPY
MODIFICATIONS
MODULATION
OXIDES
OXYGEN
POLARIZATION
STOICHIOMETRY
THICKNESS
VACANCIES
Heterointerfaces
complex oxides
oxygen vacancies
piezoresponse force microscopy