InN Thin Film Lattice Dynamics by Grazing Incidence Inelastic X-Ray Scattering

Serrano, Joaquim Rigola; Bosak, A.; Krisch, M.; Manjón, F. J.; Romero, Aldo H.; Garro, N.; Wang, Xinqiang; Yoshikawa, Akihiko; Kuball, Martin

doi:10.1103/physrevlett.106.205501

Cited by 45 publications

(32 citation statements)

References 20 publications

(27 reference statements)

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“…This value is in good agreement with experimental measurements 19 and with previous first-principles calculations. 20 In the case of rs-InN, the full structural relaxation yielded a lattice parameter of a = 4.523Å at ambient pressure and a zero-pressure bulk modulus of B 0 = 186 GPa, only slightly higher than the value measured by Uehara et al (170 ± 16 GPa). 8 For hydrostatic pressures of p = 15 GPa, just above the transition pressure, we find a bulk-modulus value of B 15 = 255 GPa.…”

Section: Ab Initio Calculationsmentioning

confidence: 62%

High-pressure lattice dynamics in wurtzite and rocksalt indium nitride investigated by means of Raman spectroscopy

et al. 2013

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We present an experimental and theoretical lattice-dynamical study of InN at high hydrostatic pressures. We perform Raman scattering measurements on five InN epilayers, with different residual strain and free electron concentrations. The experimental results are analyzed in terms of ab initio lattice-dynamical calculations on both wurtzite InN (w-InN) and rocksalt InN (rs-InN) as a function of pressure. Experimental and theoretical pressure coefficients of the optical modes in w-InN are compared, and the role of residual strain on the measured pressure coefficients is analyzed. In the case of the LO band, we analyze and discuss its pressure behavior considering the double-resonance mechanism responsible for the selective excitation of LO phonons with large wave vectors in w-InN. The pressure behavior of the L − coupled mode observed in a heavily doped n-type sample allows us to estimate the pressure dependence of the electron effective mass in w-InN. The results thus obtained are in good agreement with k · p theory. The wurtzite-to-rocksalt phase transition on the upstroke cycle and the rocksalt-to-wurtzite backtransition on the downstroke cycle are investigated, and the Raman spectra of both phases are interpreted in terms of DFT lattice-dynamical calculations.

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Section: Ab Initio Calculationsmentioning

confidence: 62%

High-pressure lattice dynamics in wurtzite and rocksalt indium nitride investigated by means of Raman spectroscopy

et al. 2013

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“…Indeed, IXS can be performed with samples as thin as 10–20 μm, which allow extending such studies up to Mbar pressure38. It is furthermore possible to work with evanescent wave fields in grazing angle conditions, which allows surface sensitive studies, measurements on thin films and multilayer systems3940.…”

Section: Discussionmentioning

confidence: 99%

Electromagnon dispersion probed by inelastic X-ray scattering in LiCrO2

et al. 2016

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Inelastic X-ray scattering with meV energy resolution (IXS) is an ideal tool to measure collective excitations in solids and liquids. In non-resonant scattering condition, the cross-section is strongly dominated by lattice vibrations (phonons). However, it is possible to probe additional degrees of freedom such as magnetic fluctuations that are strongly coupled to the phonons. The IXS spectrum of the coupled system contains not only the phonon dispersion but also the so far undetected magnetic correlation function. Here we report the observation of strong magnon–phonon coupling in LiCrO2 that enables the measurement of magnetic correlations throughout the Brillouin zone via IXS. We find electromagnon excitations and electric dipole active two-magnon excitations in the magnetically ordered phase and heavily damped electromagnons in the paramagnetic phase of LiCrO2. We predict that several (frustrated) magnets with dominant direct exchange and non-collinear magnetism show surprisingly large IXS cross-section for magnons and multi-magnon processes.

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“…The application of uniaxial expansion could be realized by bending thin films or using tensile load. TDS and IXS studies can be performed in such conditions in grazing incidence [28] or transmission geometry, respectively.…”

Section: Discussionmentioning

confidence: 99%

Soft phonon modes in rutileTiO2

Wehinger

Bosak

Jochym³

2016

Phys. Rev. B

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The lattice dynamics of TiO 2 in the rutile crystal structure was studied by a combination of thermal diffuse scattering, inelastic x-ray scattering, and density functional perturbation theory. We experimentally confirm the existence of a predicted anomalous soft transverse acoustic mode with energy minimum at q = ( 1 2 1 2 1 4 ). The phonon energy landscape of this particular branch is reported and compared to the calculation. The harmonic calculation underestimates the phonon energies but despite this the shape of both the energy landscape and the scattering intensities are well reproduced. We find a significant temperature dependence in the energy of this transverse acoustic mode over an extended region in reciprocal space, which point to a strong role of anharmonicity in line with a substantially anharmonic mode potential-energy surface. The reported low-energy branch is quite different from the ferroelectric mode that softens at the Brillouin zone center and may help explain anomalous convergence behavior in calculating TiO 2 surface properties and is potentially relevant for real behavior in TiO 2 thin films.

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InN Thin Film Lattice Dynamics by Grazing Incidence Inelastic X-Ray Scattering

Cited by 45 publications

References 20 publications

High-pressure lattice dynamics in wurtzite and rocksalt indium nitride investigated by means of Raman spectroscopy

High-pressure lattice dynamics in wurtzite and rocksalt indium nitride investigated by means of Raman spectroscopy

Electromagnon dispersion probed by inelastic X-ray scattering in LiCrO2

Soft phonon modes in rutileTiO2

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