Glassy anomalies in the heat capacity of an ordered 2-bromobenzophenone single crystal

Jeżowski, A.; Strzhemechny, M. A.; Кривчиков, А. И.; Davydova, N. A.; Szewczyk, Daria; Stepanian, S. G.; Buravtseva, L. M.; Romantsova, O. O.

doi:10.1103/physrevb.97.201201

Cited by 24 publications

(18 citation statements)

References 17 publications

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“…In the Appendix A.2 (see also Refs. [37][38][39][40][41][42] quoted therein), we discuss the behavior of D max for larger values of v where it saturates to a value D max ∼ v 2 /T c (not shown in Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

“…This value is of fundamental importance in the realm of amorphous systems, because of its correlation with the boson peak frequency, where the vibrational density of states (VDOS), normalized by the Debye law ∼ ω 2 , displays a maximum value [38][39][40]. The same boson peak phenomenology, however, is also at play in strongly anharmonic crystals [41,42]. Physically, this means that the density of the boson mediators is maximal around the boson peak frequency.…”

Section: The Resonance Conditionmentioning

confidence: 99%

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Anharmonic phonon damping enhances theTcof BCS-type superconductors

2020

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A theory of superconductivity is presented where the effect of anharmonicity, as entailed in the acoustic, or optical, phonon damping, is explicitly considered in the pairing mechanism. The gap equation is solved including diffusive Akhiezer damping for longitudinal acoustic phonons or Klemens damping for optical phonons, with a damping coefficient which, in either case, can be directly related to the Grüneisen parameter and hence to the anharmonic coefficients in the interatomic potential. The results show that the increase of anharmonicity has a strikingly non-monotonic effect on the critical temperature Tc. The optimal damping coefficient yielding maximum Tc is set by the velocity of the bosonic mediator. This theory may open up unprecedented opportunities for material design where Tc may be tuned via the anharmonicity of the interatomic potential, and presents implications for the superconductivity in the recently discovered hydrides, where anharmonicity is very strong and for which the anharmonic damping is especially relevant.

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Section: Resultsmentioning

confidence: 99%

Section: The Resonance Conditionmentioning

confidence: 99%

Anharmonic phonon damping enhances theTcof BCS-type superconductors

2020

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“…Hence, based on disorder, many theories were developed to explain the origins of Boson peak in glasses [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. In 2014, in some ordered crystals, for example, α-Cristobalite, α-Quartz, Coesite, the low-frequency part of VDOS had many common features with Boson peak in silica glass [ 19 , 20 , 21 ]. According to the published experiments, for α-Cristobalite and silica glass with matched densities, the DOS of silica glass appeared as the smoothed counterpart of DOS of the corresponding crystal, which illustrates that two systems have the same number of the excess states relative to the Debye model, the same number of states in the low-energy region, and the same specific heat.…”

Section: Introductionmentioning

confidence: 99%

Role of Anharmonic Interactions for Vibration Density of States in α-Cristobalite

et al. 2021

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The vibrational density of states (VDOS) of solids in the low-energy regime controls the thermal and transport properties of materials, such as heat capacity, heat conduction, free energy and entropy. In α-Cristobalite, the low-frequency part of vibration density of states (VDOS) has many common features with the Boson peak in silica glass of matched densities. Recent theoretical work reported that anharmonic phonon–phonon interactions were critical for the low-frequency part of VDOS in α-Cristobalite. Therefore, it is urgent to identify the role of different anharmonic interactions from first principles. In this paper, we focus on the main peak of the low-frequency part of VDOS in α-Cristobalite. Calculated by our own developed codes and first principles, we find that the quartic anharmonic interaction can increase the frequency of the peak, while the cubic anharmonic can reduce the frequency and change the shape of the peak. Meanwhile, the anharmonic interactions are critical for the temperature effect. Therefore, we calculated the temperature-dependent property of the peak. We find that the frequency of the peak is directly proportional to the temperature. The atomic displacement patterns of different temperatures also confirm the above conclusion. All our calculations converged well. Moreover, our basic results agree well with other published results. Finally, we highlight that our codes offer a general and reliable way to calculate the VDOS with temperature.

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“…What is more enigmatic is a number of reports on crystals that show the glasslike thermal properties. These crystals commonly include disorders, such as molecular disorders, minimal disorders, or orientational disorders [19][20][21][22][23]. Crystals with lone pairs or strong anharmonicity are also examples [24][25][26].…”

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confidence: 99%

Glasslike phonon excitation caused by ferroelectric structural instability

Ishii,

Yamamoto,

Sato

et al. 2021

Preprint

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Glassy anomalies in the heat capacity of an ordered 2-bromobenzophenone single crystal

Cited by 24 publications

References 17 publications

Anharmonic phonon damping enhances theTcof BCS-type superconductors

Anharmonic phonon damping enhances theTcof BCS-type superconductors

Role of Anharmonic Interactions for Vibration Density of States in α-Cristobalite

Glasslike phonon excitation caused by ferroelectric structural instability

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