title: Emergence of room-temperature ferroelectricity at reduced dimensions.
abstract: The enhancement of the functional properties of materials at reduced dimensions is crucial for continuous advancements in nanoelectronic applications. Here, we report that the scale reduction leads to the emergence of an important functional property, ferroelectricity, challenging the long-standing notion that ferroelectricity is inevitably suppressed at the scale of a few nanometers. A combination of theoretical calculations, electrical measurements, and structural analyses provides evidence of room-temperature ferroelectricity in strain-free epitaxial nanometer-thick films of otherwise nonferroelectric strontium titanate (SrTiO3). We show that electrically induced alignment of naturally existing polar nanoregions is responsible for the appearance of a stable net ferroelectric polarization in these films. This finding can be useful for the development of low-dimensional material systems with enhanced functional properties relevant to emerging nanoelectronic devices.
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: D
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA.
authors.forename: H
authors.initials: H
authors.lastname: Lu
authors.affiliation: Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Department of Materials Modeling and Characterization, Korea Institute of Materials Science, Changwon 642-831, Korea.
authors.forename: S-Y
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Physics, Temple University, Philadelphia, PA 19122, USA.
authors.forename: S-D
authors.initials: SD
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: S
authors.initials: S
authors.lastname: Ryu
authors.affiliation: Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Paudel
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: K
authors.initials: K
authors.lastname: Song
authors.affiliation: Materials Department, University of California-Santa Barbara, Santa Barbara, CA 93106-5050, USA.
authors.forename: E
authors.initials: E
authors.lastname: Mikheev
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.affiliation: Materials Department, University of California-Santa Barbara, Santa Barbara, CA 93106-5050, USA.
authors.forename: S
authors.initials: S
authors.lastname: Stemmer
authors.affiliation: Department of Physics, Boise State University, Boise, ID 83725-1570, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Tenne
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: S H
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA.
authors.forename: E Y
authors.initials: EY
authors.lastname: Tsymbal
authors.affiliation: Department of Physics, Temple University, Philadelphia, PA 19122, USA.
authors.forename: X
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: L-Q
authors.initials: LQ
authors.lastname: Chen
authors.affiliation: Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, USA. agruverman2@unl.edu eom@engr.wisc.edu.
authors.forename: A
authors.initials: A
authors.lastname: Gruverman
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA. agruverman2@unl.edu eom@engr.wisc.edu.
authors.forename: C B
authors.initials: CB
authors.lastname: Eom