Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 2018

Идентификатор DOI: 10.1088/1361-648X/aac452

Ключевые слова: LaF3, tysonite structure, DFT, electronic structure, lattice vibrations, Raman spectroscopy

Аннотация: Crystal structure of LaF3 single crystal is refined in tysonite-type trigonal unit cell P (3) over bar c1 using density functional theory calculations and Raman spectroscopy. It is shown that trigonal structure with P (3) over bar c1 space group is more energy-efficient than hexagonal structure with space group P6(3)cm. Simulated Raman spectra obtained using LDA approximation is in much better agreement with experimental data than that obtained with PBE and PBEsol functionals of GGA. The calculated frequency value of silent mode B-2 in case of hexagonal structure P6(3)cm was found to be imaginary (unstable mode), thus the energy surface obtains negative curvature with respect to the corresponding normal coordinates of the mode which leads to instability of the hexagonal structure in harmonic approximation. The A(1g) line at 214 cm(-1) in Raman spectra of LaF3 related to the translation of F2 ions along c axis can be connected with F2 ionic conductivity.

Журнал: JOURNAL OF PHYSICS-CONDENSED MATTER

Выпуск журнала: Vol. 30, Is. 25

Номера страниц: 255901

ISSN журнала: 09538984

Место издания: BRISTOL

Издатель: IOP PUBLISHING LTD

• Oreshonkov A.S. (RAS, SB, KSC, Fed Res Ctr,Kirensky Inst Phys, Krasnoyarsk 660036, Russia; Siberian Fed Univ, Krasnoyarsk 660079, Russia)
• Roginskii E.M. (Ioffe Inst, St Petersburg 194021, Russia)
• Krylov A.S. (RAS, SB, KSC, Fed Res Ctr,Kirensky Inst Phys, Krasnoyarsk 660036, Russia)
• Ershov A.A. (Siberian Fed Univ, Krasnoyarsk 660079, Russia)
• Voronov V.N. (RAS, SB, KSC, Fed Res Ctr,Kirensky Inst Phys, Krasnoyarsk 660036, Russia)

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