Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3)

Details Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3) Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3)

2004-09-10

arxiv.org/abs/cond-mat/0409273v2

Phys. Rev. B 71, 125134 (2005)

Physics

Condensed Matter

Materials Science

34 pages, 6 figures. to appear in PRB

Scientific paper

10.1103/PhysRevB.71.125134

We report first principles density functional studies using plane wave basis sets and pseudopotentials and all electron linear augmented plane wave (LAPW) of the relative stability of various ferroelectric and antiferroelectric supercells of PMN for 1:2 chemical ordering along [111] and [001]. We used linear response with density functional perturbation theory (DFPT) as implemented in the code ABINIT to compute the Born effective charges, electronic dielectric tensors, long wavelength phonon frequencies and LO-TO splittings. The polar response is different for supercells ordered along [111] and [001]. Several polar phonon modes show significant coupling with the macroscopic electric field giving giant LO-TO splittings. For [111] ordering, a polar transverse optic (TO) mode with E symmetry is found to be unstable in the ferroelectric P3m1 structure and the ground state is found to be triclinic. Multiple phonon instabilities of polar modes and their mode couplings provide the pathway for polarization rotation. The Born effective charges in PMN are highly anisotropic and this anisotropy contributes to the observed huge electromechanical coupling in PMN solid solutions.

Affiliated with

Also associated with

No associations

Rating

Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3) will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-245358