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Title: Equilibrium and stability of polarization in ultrathin ferroelectric films with ionic surface compensation.

Abstract

Thermodynamic theory is developed for the ferroelectric phase transition of an ultrathin film in equilibrium with a chemical environment that supplies ionic species to compensate its surface. Equations of state and free energy expressions are developed based on Landau-Ginzburg-Devonshire theory, using electrochemical equilibria to provide ionic compensation boundary conditions. Calculations are presented for a monodomain PbTiO{sub 3} (001) film coherently strained to SrTiO{sub 3} with its exposed surface and its electronically conducting bottom electrode in equilibrium with a controlled oxygen partial pressure. The stability and metastability boundaries of phases of different polarization are determined as a function of temperature, oxygen partial pressure, and film thickness. Phase diagrams showing polarization and internal electric field are presented. At temperatures below a thickness-dependent Curie point, high or low oxygen partial pressure stabilizes positive or negative polarization, respectively. Results are compared to the standard cases of electronic compensation controlled by either an applied voltage or charge across two electrodes. Ionic surface compensation through chemical equilibrium with an environment introduces new features into the phase diagram. In ultrathin films, a stable nonpolar phase can occur between the positive and negative polar phases when varying the external chemical potential at fixed temperature, under conditions where chargedmore » surface species are not present in sufficient concentration to stabilize a polar phase.« less

Authors:
;  [1]
  1. Center for Nanoscale Materials
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1025710
Report Number(s):
ANL/MSD/JA-68941
Journal ID: 1098-0121; TRN: US201120%%727
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B
Additional Journal Information:
Journal Volume: 84; Journal Issue: 6 ; 2011
Country of Publication:
United States
Language:
ENGLISH
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOUNDARY CONDITIONS; CURIE POINT; ELECTRIC FIELDS; ELECTRODES; EQUATIONS OF STATE; FREE ENERGY; OXYGEN; PARTIAL PRESSURE; PHASE DIAGRAMS; POLARIZATION; STABILITY; THERMODYNAMICS; THICKNESS

Citation Formats

Stephenson, G B, Highland, M J, and MSD). Equilibrium and stability of polarization in ultrathin ferroelectric films with ionic surface compensation.. United States: N. p., 2011. Web. doi:10.1103/PhysRevB.84.064107.
Stephenson, G B, Highland, M J, & MSD). Equilibrium and stability of polarization in ultrathin ferroelectric films with ionic surface compensation.. United States. https://doi.org/10.1103/PhysRevB.84.064107
Stephenson, G B, Highland, M J, and MSD). 2011. "Equilibrium and stability of polarization in ultrathin ferroelectric films with ionic surface compensation.". United States. https://doi.org/10.1103/PhysRevB.84.064107.
@article{osti_1025710,
title = {Equilibrium and stability of polarization in ultrathin ferroelectric films with ionic surface compensation.},
author = {Stephenson, G B and Highland, M J and MSD)},
abstractNote = {Thermodynamic theory is developed for the ferroelectric phase transition of an ultrathin film in equilibrium with a chemical environment that supplies ionic species to compensate its surface. Equations of state and free energy expressions are developed based on Landau-Ginzburg-Devonshire theory, using electrochemical equilibria to provide ionic compensation boundary conditions. Calculations are presented for a monodomain PbTiO{sub 3} (001) film coherently strained to SrTiO{sub 3} with its exposed surface and its electronically conducting bottom electrode in equilibrium with a controlled oxygen partial pressure. The stability and metastability boundaries of phases of different polarization are determined as a function of temperature, oxygen partial pressure, and film thickness. Phase diagrams showing polarization and internal electric field are presented. At temperatures below a thickness-dependent Curie point, high or low oxygen partial pressure stabilizes positive or negative polarization, respectively. Results are compared to the standard cases of electronic compensation controlled by either an applied voltage or charge across two electrodes. Ionic surface compensation through chemical equilibrium with an environment introduces new features into the phase diagram. In ultrathin films, a stable nonpolar phase can occur between the positive and negative polar phases when varying the external chemical potential at fixed temperature, under conditions where charged surface species are not present in sufficient concentration to stabilize a polar phase.},
doi = {10.1103/PhysRevB.84.064107},
url = {https://www.osti.gov/biblio/1025710}, journal = {Phys. Rev. B},
number = 6 ; 2011,
volume = 84,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 2011},
month = {Sat Jan 01 00:00:00 EST 2011}
}