Semi-empirical Hartree-Fock calculations for KNbO3 and KTaO 3

R. I. Eglitis; A. V. Postnikov; G. Borstel

doi:10.1117/12.266525

Semi-empirical Hartree-Fock calculations for KNbO₃ and KTaO ₃

R. I. Eglitis
, A. V. Postnikov
, G. Borstel

Laboratory of Computer Modeling of Electronic Structure of Solids, Institute of Solid State Physics

Osnabrück University

Research output: Contribution to journal › Conference article › peer-review

Abstract

As a first step in modeling the electronic structure of Perovskite-type ferroelectric mixed crystals K(Nb,Ta)O₃, semiempirical calculations for pure KNbO₃ and KTaO₃ are performed with the intermediate neglect of the differential overlap (INDO) quantum chemical method. The calculations are mostly done for 40-atom supercells. The choice of the INDO parameters based on the comparison of results with ab initio and experimental data is discussed. INDO results for the equilibrium geometry and the (Gamma) -TO phonon frequencies are given. The results show that the accuracy of the INDO method is sufficient for reliably reproducing the energy differences on the order of 1 mRy (per formula unit) scale which are typical when dealing with ferroelectric instabilities.

Original language	English
Pages (from-to)	144-149
Number of pages	6
Journal	Proceedings of SPIE - The International Society for Optical Engineering
Volume	2967
DOIs	https://doi.org/10.1117/12.266525
Publication status	Published - 1997
Event	Optical Inorganic Dielectric Materials and Devices - Riga, Latvia Duration: 26 Aug 1996 → 26 Aug 1996

Keywords

Ferroelectrics
Frozen phonons
INDO method
Perovskites
Phase transitions

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10.1117/12.266525

Cite this

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title = "Semi-empirical Hartree-Fock calculations for KNbO3 and KTaO 3",

abstract = "As a first step in modeling the electronic structure of Perovskite-type ferroelectric mixed crystals K(Nb,Ta)O3, semiempirical calculations for pure KNbO3 and KTaO3 are performed with the intermediate neglect of the differential overlap (INDO) quantum chemical method. The calculations are mostly done for 40-atom supercells. The choice of the INDO parameters based on the comparison of results with ab initio and experimental data is discussed. INDO results for the equilibrium geometry and the (Gamma) -TO phonon frequencies are given. The results show that the accuracy of the INDO method is sufficient for reliably reproducing the energy differences on the order of 1 mRy (per formula unit) scale which are typical when dealing with ferroelectric instabilities.",

keywords = "Ferroelectrics, Frozen phonons, INDO method, Perovskites, Phase transitions",

author = "Eglitis, \{R. I.\} and Postnikov, \{A. V.\} and G. Borstel",

year = "1997",

doi = "10.1117/12.266525",

language = "English",

volume = "2967",

pages = "144--149",

journal = "Proceedings of SPIE - The International Society for Optical Engineering",

issn = "0277-786X",

publisher = "SPIE",

note = "Optical Inorganic Dielectric Materials and Devices ; Conference date: 26-08-1996 Through 26-08-1996",

}

TY - JOUR

T1 - Semi-empirical Hartree-Fock calculations for KNbO3 and KTaO 3

AU - Eglitis, R. I.

AU - Postnikov, A. V.

AU - Borstel, G.

PY - 1997

Y1 - 1997

N2 - As a first step in modeling the electronic structure of Perovskite-type ferroelectric mixed crystals K(Nb,Ta)O3, semiempirical calculations for pure KNbO3 and KTaO3 are performed with the intermediate neglect of the differential overlap (INDO) quantum chemical method. The calculations are mostly done for 40-atom supercells. The choice of the INDO parameters based on the comparison of results with ab initio and experimental data is discussed. INDO results for the equilibrium geometry and the (Gamma) -TO phonon frequencies are given. The results show that the accuracy of the INDO method is sufficient for reliably reproducing the energy differences on the order of 1 mRy (per formula unit) scale which are typical when dealing with ferroelectric instabilities.

AB - As a first step in modeling the electronic structure of Perovskite-type ferroelectric mixed crystals K(Nb,Ta)O3, semiempirical calculations for pure KNbO3 and KTaO3 are performed with the intermediate neglect of the differential overlap (INDO) quantum chemical method. The calculations are mostly done for 40-atom supercells. The choice of the INDO parameters based on the comparison of results with ab initio and experimental data is discussed. INDO results for the equilibrium geometry and the (Gamma) -TO phonon frequencies are given. The results show that the accuracy of the INDO method is sufficient for reliably reproducing the energy differences on the order of 1 mRy (per formula unit) scale which are typical when dealing with ferroelectric instabilities.

KW - Ferroelectrics

KW - Frozen phonons

KW - INDO method

KW - Perovskites

KW - Phase transitions

UR - https://www.scopus.com/pages/publications/58049185192

U2 - 10.1117/12.266525

DO - 10.1117/12.266525

M3 - Conference article

AN - SCOPUS:58049185192

SN - 0277-786X

VL - 2967

SP - 144

EP - 149

JO - Proceedings of SPIE - The International Society for Optical Engineering

JF - Proceedings of SPIE - The International Society for Optical Engineering

T2 - Optical Inorganic Dielectric Materials and Devices

Y2 - 26 August 1996 through 26 August 1996

ER -

Semi-empirical Hartree-Fock calculations for KNbO₃ and KTaO ₃

Abstract

Keywords

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