Infrared Properties of Ca<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">F</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, Sr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">F</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, and Ba<mml:math xmlns:mml="h

Kaiser, W.; Spitzer, W. G.; Kaiser, R.; Howarth, L. E.

doi:10.1103/physrev.127.1950

Cited by 214 publications

(66 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…While the Born charges are similar for ACBN0 and PBE (2.33 e and 2.34 e, respectively), there are significant differences in the highfrequency dielectric constant ϵ 1 (2.083 and 2.305, respectively). The value obtained using ACBN0 is closer to the experimental ϵ 1 (2.045) 97 than that obtained using PBE.…”

Section: Validation With Experimentsmentioning

confidence: 67%

“…As a testbed, calcium fluoride, CaF 2 , is chosen, because of the ample available experimental data. 81,[95][96][97] CaF 2 has been extensively used in optical devices due to its low refractive index, wide band gap, low dispersion, and large broadband radiation transmittance. [108][109][110] A package implementing a minimalist AFLOW-Python approach to high-throughput ab-initio calculations for the generation of tight-binding hamiltonians and the calculation with the ACBN0 functional (AFLOWπ) 111 is used to obtain the ACBN0 electronic structure of CaF 2 .…”

Section: Validation With Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

An efficient and accurate framework for calculating lattice thermal conductivity of solids: AFLOW—AAPL Automatic Anharmonic Phonon Library

et al. 2017

View full text Add to dashboard Cite

One of the most accurate approaches for calculating lattice thermal conductivity, κ ' , is solving the Boltzmann transport equation starting from third-order anharmonic force constants. In addition to the underlying approximations of ab-initio parameterization, two main challenges are associated with this path: high computational costs and lack of automation in the frameworks using this methodology, which affect the discovery rate of novel materials with ad-hoc properties. Here, the Automatic Anharmonic Phonon Library (AAPL) is presented. It efficiently computes interatomic force constants by making effective use of crystal symmetry analysis, it solves the Boltzmann transport equation to obtain κ ' , and allows a fully integrated operation with minimum user intervention, a rational addition to the current high-throughput accelerated materials development framework AFLOW. An "experiment vs. theory" study of the approach is shown, comparing accuracy and speed with respect to other available packages, and for materials characterized by strong electron localization and correlation. Combining AAPL with the pseudo-hybrid functional ACBN0 is possible to improve accuracy without increasing computational requirements.

show abstract

Section: Validation With Experimentsmentioning

confidence: 67%

Section: Validation With Experimentsmentioning

confidence: 99%

An efficient and accurate framework for calculating lattice thermal conductivity of solids: AFLOW—AAPL Automatic Anharmonic Phonon Library

et al. 2017

View full text Add to dashboard Cite

show abstract

“…I n particular, if the frequency of subsidiary features is less than vs, the harmonic approximation gives for v, a value close t o the experimental ones. This is the situation for the high-frequency part of the dispersion curve for Cap,, where the frequency of the subsidiary pole is equal t o 328 cm-l [27]. If the frequency of the subsidiary feature is greater than vs, the use of the harmonic approximation leads t o overestimated values of Y, (surface vibrations in NaC1).…”

Section: Discussionmentioning

confidence: 90%

Experimental Study of Surface Optical Modes in Ionic Crystal Slabs

Bryksin

Gerbstein

Mirlin

1972

Physica Status Solidi (b)

View full text Add to dashboard Cite

Surface optical vibrations have been revealed and investigated in slabs of a number of alkali halide crystals and crystals of CaF, and CdF,. The measurements were carried out by the attenuated total reflection technique. The frequency dependence of reflection coefficient has been calculated in accordance with the experimental set-up. For NaCl and CaF, crystals dispersion curves of the surface modes have been measured a t room and liquid nitrogen temperatures.

show abstract

“…The general theory of the tunneling splitting in JT systems was first worked out in 22 , and for the tunneling between the orthorhombic minima of the full T 2g ⊗ (e g + t 2g ) problem under consideration the following expression for the tunneling splitting δ 0 of the ground vibrational state was obtained under the approximation K T ≈ K E 12,13 : …”

Section: Energy Barrier and Tunneling Splittingmentioning

confidence: 99%

Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal

Жевстовских

Берсукер

Гудков

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

A methodology is worked out to retrieve the numerical values of all the main parameters of the six-dimensional adiabatic potential energy surface (APES) of a polyatomic system with a quadratic T-term Jahn-Teller effect (JTE) from ultrasound experiments. The method is based on a verified assumption that ultrasound attenuation and speed encounter anomalies when the direction of propagation and polarization of its wave of strain coincides with the characteristic directions of symmetry breaking in the JTE. For the SrF2:Cr crystal, employed as a basic example, we observed anomaly peaks in the temperature dependence of attenuation of ultrasound at frequencies of 50-160 MHz in the temperature interval of 40-60 K for the wave propagating along the [110] direction, for both the longitudinal and shear modes, the latter with two polarizations along the [001] and [110] axes, respectively. We show that these anomalies are due to the ultrasound relaxation by the system of non-interacting Cr 2+ JT centers with orthorhombic local distortions. The interpretation of the experimental findings is based on the T2g ⊗ (eg + t2g) JTE problem including the linear and quadratic terms of vibronic interactions in the Hamiltonian and the same-symmetry modes reduced to one interaction mode. Combining the experimental results with a theoretical analysis we show that on the complicated six-dimensional APES of this system with three tetragonal, four trigonal, and six orthorhombic extrema points, the latter are global minima, while the former are saddle points, and we estimate numerically all the main parameters of this surface, including the linear and quadratic vibronic coupling constants, the primary force constants, the coordinates of all the extrema points and their energies, the energy barrier between the orthorhombic minima, and the tunneling splitting of the ground vibrational states. To our knowledge, such a based-on-experimental-data numerical reconstruction of the APES of a JTE problem in the five-dimensional space of all active tetragonal and trigonal displacements is realized here for the first time.

show abstract

Infrared Properties of CaF2, SrF2, and Ba
W. Kaiser¹,
W. G. Spitzer²,
R. Kaiser³
et al.

Cited by 214 publications

References 16 publications

An efficient and accurate framework for calculating lattice thermal conductivity of solids: AFLOW—AAPL Automatic Anharmonic Phonon Library

An efficient and accurate framework for calculating lattice thermal conductivity of solids: AFLOW—AAPL Automatic Anharmonic Phonon Library

Experimental Study of Surface Optical Modes in Ionic Crystal Slabs

Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal

Contact Info

Product

Resources

About

Infrared Properties of CaF2, SrF2, and BaW. Kaiser1, W. G. Spitzer2, R. Kaiser3 et al.

Cited by 214 publications

References 16 publications

An efficient and accurate framework for calculating lattice thermal conductivity of solids: AFLOW—AAPL Automatic Anharmonic Phonon Library

An efficient and accurate framework for calculating lattice thermal conductivity of solids: AFLOW—AAPL Automatic Anharmonic Phonon Library

Experimental Study of Surface Optical Modes in Ionic Crystal Slabs

Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal

Contact Info

Product

Resources

About

Infrared Properties of CaF2, SrF2, and Ba
W. Kaiser¹,
W. G. Spitzer²,
R. Kaiser³
et al.