Properties of epitaxial (110) BaTiO3films from first principles

Abstract

A first-principle-based effective Hamiltonian approach is used to simulate the temperature-versus-misfit strain phase diagram of epitaxial (110) BaTiO 3 (BTO) thin films. Unusual features are discovered that significantly differ from those found in BTO films grown along the "usual" [001] direction. Examples include the independency of the Curie temperature with compressive strain, and the existence of specific monoclinic and triclinic phases near room temperature. These low-symmetry phases are associated with a rapid strain-induced rotation of the polarization and possess large piezoelectric and dielectric responses. Our atomistic technique provides an insight into these novel features, as well as, other predicted phenomena.

Effect of crystal orientation on the phase diagrams, dielectric and piezoelectric properties of epitaxial BaTiO3 thin films

“…(1) Paraelectric: P(p) (P 2 1 = P 2 2 = P 2 3 = 0; 39 especially the existence of specific monoclinic and triclinic phases near room temperature, simulated by a first-principles-based effective Hamiltonian approach, though the area of each phase is a little different. As we can see, the phase diagram of (110)-oriented BTO films is significantly different from that of BTO films grown along the conventional [001] direction shown in the inset of Fig.…”

“…Recent first-principles calculations have suggested that a complex phase transition process, tuned by epitaxial strain, can occur in (111)-oriented PbTiO 3 (PTO) and BTO films and an unexpected triclinic phase and three distinct monoclinic phases may exist in (110)-oriented BTO films. 38,39 Despite these important investigations, it is still not well understood that how orientations affect the physical properties of ferroelectric thin films. For example, Gui et al 39 found that the Curie temperature T C of the (110)-oriented BTO thin film was independent of compressive in-plane strain by using first-principles-based effective Hamiltonian approach, unlike (001)-oriented BTO films, 40,41 although positive in-plane strain does.…”

“…38,39 Despite these important investigations, it is still not well understood that how orientations affect the physical properties of ferroelectric thin films. For example, Gui et al 39 found that the Curie temperature T C of the (110)-oriented BTO thin film was independent of compressive in-plane strain by using first-principles-based effective Hamiltonian approach, unlike (001)-oriented BTO films, 40,41 although positive in-plane strain does. However, recently, Shimizu et al 42 reported that a large increase in T C exhibited in both the (001)-and (110)-oriented BTO thin films with the thickness of 100 nm.…”

Tuning and optimizing properties of ferroelectric films grown on a single substrate: A first-principles-based study

“…Ferroelectric materials have been intensively studied, partly because of their useful properties that can be put into use in devices [1,2]. Among many factors that greatly affect their properties, epitaxial strain experienced by ferroelectric films grown along the [001] pseudocubic direction is one of the most investigated and manipulatable aspects [3][4][5][6][7][8][9][10][11]. For instance, it allows to induce a large electrical polarization and drastically shift the paraelectric-to-ferroelectric transition temperature [12,13].…”

Chemical strain-dependent two-dimensional transport at RAlO3/SrTiO3 interfaces (R=La,NdLi1, Yang2, Bai3 et al. 2016Phys. Rev. B6030View full textAdd to dashboardCite

“…This is in drastic contrast with cases of typical (001) ferroelectric films, such as BaTiO 3 , PbTiO 3 , and BiFeO 3 , in which the out-of-plane polarization decreases with the increase of tensile strain. [46][47][48][49] To further understand this increase of P i in (ReAO) 5 /(STO) 9 , it is informative to recall that one can also write that P i = ε 0 ε r E, where ε r is the dielectric constant and E is the electric field within the ReAO layers. For all the (ReAO) 5 /(STO) 9 supercell we considered, the ReAO thickness (5 u.c.)…”