Ultrafast phonon diffuse scattering as a tool for observing chiral phonons in monolayer hexagonal lattices

Britt, Tristan; Siwick, Bradley J.

doi:10.1103/physrevb.107.214306

Cited by 3 publications

(3 citation statements)

References 58 publications

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“…Consequently, the optimization of heat transport, particularly in practical applications, has become the linchpin of effective thermal management, enhancing energy efficiency and advancing the development of nextgeneration materials. [1][2][3][4][5] Within the burgeoning field of heat transport studies, researchers have predominantly focused on exploring the dual facets of particle dynamics [6][7][8] and wave mechanics [9][10][11] pertaining to phonons. Remarkable progress has been achieved in controlling mid-frequency and high-frequency phonons through these methodologies.…”

Section: Introductionmentioning

confidence: 99%

Phonon resonance modulation in weak van der Waals heterostructures: Controlling thermal transport in graphene–silicon nanoparticle systems

Li 李,

Liu 刘,

Hu 胡

2024

Chinese Phys. B

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The drive for efficient thermal management has intensified with the miniaturization of electronic devices. This study explores the modulation of phonon transport within graphene by introducing silicon nanoparticles influenced by van der Waals forces. Our approach involves the application of non-equilibrium molecular dynamics to assess thermal conductivity while varying the interaction strength, leading to a noteworthy reduction in thermal conductivity. Furthermore, we observe a distinct attenuation in length-dependent behavior within the graphene-nanoparticles system. Our exploration combines wave packet simulations with phonon transmission calculations, aligning with a comprehensive analysis of the phonon transport regime to unveil the underlying physical mechanisms at play. Lastly, we conduct transient molecular dynamics simulations to investigate interfacial thermal conductance between the nanoparticles and the graphene, revealing an enhanced TBC. This research not only contributes to our understanding of phonon transport but also opens a new degree of freedom for utilizing van der Waals nanoparticle-induced resonance, offering promising avenues for the modulation of thermal properties in advanced materials and enhancing their performance in various technological applications.

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Section: Introductionmentioning

confidence: 99%

Phonon resonance modulation in weak van der Waals heterostructures: Controlling thermal transport in graphene–silicon nanoparticle systems

Li 李,

Liu 刘,

Hu 胡

2024

Chinese Phys. B

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“…Ultrafast electron diffuse scattering (UEDS) enables us to directly image the nonequilibrium phonon populations with time and momentum resolutions. − UEDS has been widely applied in the past to layered and 2D materials, ,, making it suitable to explore the emergence of chiral phonons in real time in TMDs . We thus expect it to provide a suitable route to experimentally detect the occurrences of vibrational dichroism.…”

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confidence: 99%

“…60−64 UEDS has been widely applied in the past to layered and 2D materials, 60,65,66 making it suitable to explore the emergence of chiral phonons in real time in TMDs. 67 We thus expect it to provide a suitable route to experimentally detect the occurrences of vibrational dichroism. In the following, we show that the nonequilibrium phonon populations established by absorption of circularly polarized light give rise to distinctive fingerprints in the measured UEDS signal, characterized by a reversal of UEDS intensity upon switching of light polarization.…”

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confidence: 99%

Vibrational Dichroism of Chiral Valley Phonons

Pan,

Caruso

2023

Nano Lett.

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Valley degrees of freedom in transition metal dichalcogenides thoroughly influence electron−phonon coupling and its nonequilibrium dynamics. We conducted a first-principles study of the quantum kinetics of chiral phonons following valley-selective carrier excitation with circularly polarized light. Our numerical investigations treat the ultrafast dynamics of electrons and phonons on equal footing within a parameter-free ab initio framework. We report the emergence of valley-polarized phonon populations in monolayer MoS 2 that can be selectively excited at either the K or K′ valleys depending on the light helicity. The resulting vibrational state is characterized by a distinctive chirality, which lifts time-reversal symmetry of the lattice on transient time scales. We show that chiral valley phonons can further lead to fingerprints of vibrational dichroism detectable by ultrafast diffuse scattering and persist beyond 10 ps. The valley polarization of nonequilibrium phonon populations could be exploited as an information carrier, thereby extending the paradigm of valleytronics to the domain of vibrational excitations.

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A momentum-resolved view of polaron formation in materials

Britt,

Caruso,

Siwick

2024

npj Comput Mater

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An ab-initio computational methodology for interrogating the phonon contribution to polaron formation in real materials is developed that can be directly compared to experiment. Using LiF as an example, we show that the recent ab-initio theory of Sio et al.1 makes predictions of the momentum- and branch dependent phonon amplitudes in polaron quasiparticles that are testable using ultrafast electron diffuse scattering (UEDS) and related techniques. The large electron polaron in LiF has UEDS signatures that are qualitatively similar to those expected from a simple isotropic strain field model, but the small hole polaron exhibits a profoundly anisotropic UEDS pattern that is in poor agreement with an isotropic strain field. We also show that these polaron diffuse scattering signatures are directly emblematic of the underlying polaron wavefunction. The combination of new time and momentum resolved experimental probes of nonequilibrium phonons with novel computational methods promises to complement the qualitative results obtained via model Hamiltonians with a first principles, material-specific quantitative understanding of polarons and their properties.

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Ultrafast phonon diffuse scattering as a tool for observing chiral phonons in monolayer hexagonal lattices

Cited by 3 publications

References 58 publications

Phonon resonance modulation in weak van der Waals heterostructures: Controlling thermal transport in graphene–silicon nanoparticle systems

Phonon resonance modulation in weak van der Waals heterostructures: Controlling thermal transport in graphene–silicon nanoparticle systems

Vibrational Dichroism of Chiral Valley Phonons

A momentum-resolved view of polaron formation in materials

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