Domain wall fluctuations in ferroelectrics coupled to strain

Abstract

Using a Ginzburg--Landau--Devonshire model that includes the coupling of polarization to strain, we calculate the fluctuation spectra of ferroelectric domain walls. The influence of the strain coupling differs between 180 degree and 90 degree walls due to the different strain profiles of the two configurations. The finite speed of acoustic phonons, $v_s$, retards the response of the strain to polarization fluctuations, and the results depend on $v_s$. For $v_s \to \infty$, the strain mediates an instantaneous electrostrictive interaction, which is long-range in the 90 degree wall case. For finite $v_s$, acoustic phonons damp the wall excitations, producing a continuum in the spectral function. As $v_s\ to 0$, a gapped mode emerges, which corresponds to the polarization oscillating in a fixed strain potential

Prospects and applications near ferroelectric quantum phase transitions: a key issues review

“…Anisotropic elastic effects in ferroelectris have also been studied [61]. The resulting domains have sufficiently slow dynamics, perhaps due to their physical extent or to pinning, that they do not seem to contribute to low-temperature thermodynamic quantities on measurable time-scales studied to date [22].…”

Revisiting the broadband dielectric properties of high‐sensitivity piezoelectric BiScO3–PbTiO3: Size effects

“…When an external weak electric field is applied, the domain walls move slightly, emitting acoustic waves through coupling of polarization to strain (see, Ref. ). The spectra of emitted waves would be quite broadband, as movement of the walls is actually jerky and associated with Barkhausen noise .…”

Superdomain dynamics in ferroelectric-ferroelastic films: Switching, jamming, and relaxation

“…The criterion for ferroelasticity originally suggested by Toledano [110] was that it is necessary and sufficient that the crystal class change at the ferroelectric transition, such that rhombohedral-rhombohedral transitions (e.g., LiNbO3) are not ferroelectric, nor are othorhombic-orthorhombic (e.g., KTiOPO4 Although the present review emphasizes net motion of domain walls, we note that oscillation of such walls is also a topic of current interest. [113][114][115] Chu et al [116] have commented that the major contribution to the dielectric response is from the polarization fluctuations on the 90°-domain walls, which are more mobile than those inside the domains. The theory [113,114] predicts a gap energy in the acoustic phonon/soft-optic mode spectrum at a few GHz, which appears to have been found in ferroelectric trissarcosine calcium chloride.…”

“…[113][114][115] Chu et al [116] have commented that the major contribution to the dielectric response is from the polarization fluctuations on the 90°-domain walls, which are more mobile than those inside the domains. The theory [113,114] predicts a gap energy in the acoustic phonon/soft-optic mode spectrum at a few GHz, which appears to have been found in ferroelectric trissarcosine calcium chloride. [115] Such low-frequency overdamped modes can arise from different physical mechanisms, including dynamics of incommensurate domain structures, and in a few cases have been shown [117] to be diffusive, with linewidth varying as q 2 , where q is the momentum transfer; this q 2 -dependence is a signature of hydrodynamic diffusion and in general supports the basic hydrodynamic model of domain wall motion under stress.…”