Raman-active 
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 phonon in 
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: Electron-phonon interaction and anharmonicity

Ponosov, Yu. S.; Streltsov, S. V.

doi:10.1103/physrevb.96.214503

Cited by 10 publications

(8 citation statements)

References 43 publications

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“…The importance of energy renormalization effects is also reflected in the qualitative behavior of ω 0ν as a function of T . Namely, some experimental measurements reported a constant value or even a small increase of the E 2g frequency at lower values of T (i.e., up to about 200 K) [17,19,24,28], which is only observed here when λ n (ω) is included [compare Figs. 2(b) and 2(e)].…”

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confidence: 63%

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confidence: 94%

“…The presented ranges include the results obtained with and without the vertex corrections and with 1/τimp = 5 − 20 meV. The experimental [15,16,18,19,28] and previous theoretical [37] results are shown for comparison. All the reported values are in meV.…”

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confidence: 99%

“…Remarkably, in MgB 2 , both the state-of-the-art adiabatic and NA descriptions break down. Namely, the Raman measurements reveal an unusually large linewidth of the E 2g phonon peaked at around 77 meV [15][16][17][18][19], which falls just between the adiabatic (67 meV) and NA (94 meV) values [6,14].In order to resolve this discrepancy numerous explanations emerged. A significant temperature dependence of the phonon spectrum lead numerous studies to ascribe the foregoing anomalies to the anharmonicity [20][21][22][23][24].…”

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confidence: 99%

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Nonadiabatic coupling effects in MgB2 reexamined

Novko

2018

Phys. Rev. B

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The unusual Raman spectrum of MgB2 and its formidable temperature dependence are successfully reproduced by means of a parameter-free ab initio nonadiabatic theory that accounts for the electron-hole pair scattering mechanisms with the system phonons. This example turns out to be a prototypical case where a strong nonadiabatic renormalization of the phonon frequency is partially washed out by the aforementioned scattering events, bringing along a characteristic temperature dependence. Both electron-hole pair lifetime and energy renormalization effects due to dynamical electron-phonon coupling turn out to play a crucial role. This theory could aid in comprehending other Raman spectra characterized with unconventionally strong electron-phonon interaction.Recent years have witnessed an ample interest in nonadiabatic (NA) coupling effects [1,2] and their intriguing impact on the vibrational properties of solids [3]. Particularly strong deviations from the adiabatic phonon spectrum were observed for the long wavelength (q ≈ 0) modes of carbon-based materials, such as metallic carbon nanotubes [4,5], graphite intercalation compounds [6-9], graphene [10][11][12], and boron-doped diamond [13]. The corresponding NA theory based in first principles is well established and in most instances the calculated NA phonon frequencies complement the experiments quite accurately [6,10,14]. Remarkably, in MgB 2 , both the state-of-the-art adiabatic and NA descriptions break down. Namely, the Raman measurements reveal an unusually large linewidth of the E 2g phonon peaked at around 77 meV [15][16][17][18][19], which falls just between the adiabatic (67 meV) and NA (94 meV) values [6,14].In order to resolve this discrepancy numerous explanations emerged. A significant temperature dependence of the phonon spectrum lead numerous studies to ascribe the foregoing anomalies to the anharmonicity [20][21][22][23][24]. Conversely, it was shown that the phonon-phonon corrections constitute only a small portion of the E 2g phonon linewidth and the frequency shift, as well as bring about a minor temperature change [16,[25][26][27][28]. The effects of the electron relaxation processes (e.g., higher order electron-phonon scattering) on the phonon spectrum were also taken into consideration, since it was shown that high-frequency optical modes in metallic systems might be rather sensitive to these processes when q ≈ 0 [29][30][31][32][33][34][35]. In fact, few studies have qualitatively demonstrated that it is precisely this mechanism that prompts the breakdown of the standard adiabatic and NA theories in MgB 2 [6,16,19,27,36,37]. Nevertheless, a concomitant NA theory based in first principles that can resolve this controversy is still absent. Such an in-depth quantitative survey of the NA effects is of great fundamental interest, e.g., for comprehending superconductivity mechanisms, especially in MgB 2 , * dino.novko@gmail.com where the unusually strong interaction between the E 2g phonon and electrons is suspected to underly the electron pairing p...

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confidence: 63%

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confidence: 94%

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confidence: 99%

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confidence: 99%

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Nonadiabatic coupling effects in MgB2 reexamined

Novko

2018

Phys. Rev. B

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“…In the typical ionic compound, cesium halides (e.g., CsCl, CsBr, and CsI), a lowtemperature anharmonicity was found with anharmonic Cs displacements and short phonon lifetime, compared with the anharmonic behavior commonly occurring at higher temperatures [49,50]. The remarkable progress of phonon an-harmonicity promotes a deep understanding of thermoelectrics [39,46,48], ferroelectrics [51,52], multiferroics [53][54][55], high-T c superconductors [56][57][58], etc. Due to the importance of phonon anharmonicity in advanced materials, it is valuable to have a comprehensive review of phonon anharmonicity, as is the motivation of the present article.…”

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confidence: 99%

Phonon anharmonicity: a pertinent review of recent progress and perspective

Wei

Sun

et al. 2021

Sci. China Phys. Mech. Astron.

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Anharmonic lattice vibrations play pivotal roles in the thermal dynamics in condense matters and affect how the atoms interact and conduct heat. An in-depth understanding of the microscopic mechanism of phonon anharmonicity in condensed systems is critical for developing better functional and energy materials. In recent years, various novel behaviors in condense matters driven by phonon anharmonic effects were discovered, such as soft mode phase transition, negative thermal expansion (NTE), multiferroicity, ultralow thermal conductivity (κ), high thermal resistance, and high-temperature superconductivity. These properties have endowed anharmonicity with many promising applications and provided remarkable opportunities for developing "Anharmonicity Engineering"-regulating heat transport towards excellent performance in materials. In this work, we review the recent development of studies on phonon anharmonic effect and summarize its origin, mechanism, research methods, and applications. Besides, the remaining challenges, future trends, and prospects of phonon anharmonicity are also discussed.

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Electronic Transport and Interaction of Lattice Dynamics in Topological Nodalline Semimetal HfAs₂ Single Crystals

Muhammad,

Hussain,

Islam

et al. 2024

Adv Funct Materials

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Topological semimetals represent a novel class of quantum materials displaying non‐trivial topological states that host Dirac/Weyl fermions. The intersection of Dirac/Weyl points gives rise to essential properties in a wide range of innovative transport phenomena, including extreme magnetoresistance, high mobilities, weak antilocalization, electron hydrodynamics, and various electro‐optical phenomena. In this study, the electronic, transport, phonon scattering, and interrelationships are explored in single crystals of the topological semimetal HfAs2. It reveals a weak antilocalization effect at low temperatures with high carrier density, which is attributed to perfectly compensated topological bulk and surface states. The angle‐resolved photoemission spectroscopy (ARPES) results show anisotropic Fermi surfaces and surface states indicative of the topological semimetal, further confirmed by first‐principle density functional theory (DFT) calculations. Moreover, the lattice dynamics in HfAs2 are investigated both with the Raman scattering and density functional theory. The phonon dispersion, density of states, lattice thermal conductivity, and the phonon lifetimes are computed to support the experimental findings. The softening of phonons, the broadening of Raman modes, and the reduction of phonon lifetimes with temperature suggest the enhancement of phonon anharmonicity in this new topological material, which is crucial for boosting the thermoelectric performance of topological semimetals.

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Raman-active E2g phonon in MgB2 : Electron-phonon interaction and anharmonicity

Cited by 10 publications

References 43 publications

Nonadiabatic coupling effects in MgB2 reexamined

Nonadiabatic coupling effects in MgB2 reexamined

Phonon anharmonicity: a pertinent review of recent progress and perspective

Electronic Transport and Interaction of Lattice Dynamics in Topological Nodalline Semimetal HfAs₂ Single Crystals

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Raman-active E2g phonon in MgB2 : Electron-phonon interaction and anharmonicity

Cited by 10 publications

References 43 publications

Nonadiabatic coupling effects in MgB2 reexamined

Nonadiabatic coupling effects in MgB2 reexamined

Phonon anharmonicity: a pertinent review of recent progress and perspective

Electronic Transport and Interaction of Lattice Dynamics in Topological Nodalline Semimetal HfAs2 Single Crystals

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Product

Resources

About

Electronic Transport and Interaction of Lattice Dynamics in Topological Nodalline Semimetal HfAs₂ Single Crystals