Quantum confinement of coherent acoustic phonons in transferred single-crystalline bismuth nanofilms

He, Feng; Walker, Emily; Zhou, Yongjian; Muschinske, Sarah E.; Bank, Seth R.; Wang, Yaguo

doi:10.1063/5.0007168

Cited by 6 publications

(3 citation statements)

References 46 publications

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“…From the temporal evolution of the radius (fig. S3), we have estimated the expansion speed of the Bi NP as ~200 m s −1 , slower than the elastic wave propagation speed of Bi with its sound velocity of 1790 m s −1 ( 26 ).…”

Section: Resultsmentioning

confidence: 99%

Inducing thermodynamically blocked atomic ordering via strongly driven nonequilibrium kinetics

et al. 2021

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Section: Resultsmentioning

confidence: 99%

Inducing thermodynamically blocked atomic ordering via strongly driven nonequilibrium kinetics

et al. 2021

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“…Bimuthene is a newly reported 2D quantum material by us and other groups, which has exhibited promising potential use in nonlinear optics, topological materials, and catalysis. − Although the generation of optical phonons in bulk Bi films had been previously reported, studies on the coherent phonon modulation in 2D Bi with quantum confinement effect are rather scant. − In this work, we managed to generate size-dependent phonon coherence of bulk Bi, multi-layer Bi, and few-layer Bi by an ultrafast femtosecond laser pulse and made a systematic comparison thorough a combination of computation, femtosecond transient absorption, and reflectance spectroscopic methods. The results showed that with the decrease of the thickness of Bi materials, the carrier excited by a femtosecond ultrafast laser became more difficult to transfer and the chemical bond was softened, inducing shortened decoherence time and red-shifted vibration frequency.…”

mentioning

confidence: 99%

Ultrafast Generation of Coherent Phonons in Two-Dimensional Bismuthene

Liu

Zhang³

et al. 2022

J. Phys. Chem. Lett.

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Coherent phonons generated through regulation of lattice oscillation via ultrafast laser pulses or X-rays have been desired in various fields, including optoelectronics, thermal and quantum information, and communications. Phonon coherence of two-dimensional (2D) materials is particularly attractive as it enables controllable information transmission but is challenging as the weak interplanar coupling makes phonon excitation extremely difficult. Herein we managed to generate size-dependent phonon coherence from bulk Bi to few-layer bismuthene by an ultrafast femtosecond laser pulse and made a systematic comparison thorough a combination of computation, transient absorption, and reflectance spectroscopic methods. The results witnessed the A 1g phonon excitation in all of the three Bi materials with distinct thicknesses, and the quantum size effect of 2D materials caused phonon confinement and eventual bond softening manifested as a red-shifted vibration frequency and shortened decoherence time compared with those of their bulk counterpart. This study offers new perspectives for tailoring coherent phonons in 2D materials for quantum science and technology including quantum communication, computing, and design of novel quantum devices, etc.

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“…Recently, phonons have been used to couple distant quantum systems, facilitating quantum entanglement of two qubits (Bienfait et al, 2019). This transfer of coherent phonons has also been observed experimentally between bismuth nanofilms and a glass substrate (He et al, 2020). Studies of longitudinal optical phonons in GaAs/Al x Ga 1−x As quantum core-shell wires have shown that phonons influence the mobility of electrons, and that mobility can be achieved by core-shell wires of thicker shells (Dat and Hai, 2019).…”

Section: Introductionmentioning

confidence: 85%

Electron-LO-phonon Intrasubband Scattering Rates in a Hollow Cylinder Under the Influence of a Uniform Axial Applied Magnetic Field

Masale

Tshipa

2021

Preprint

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Scattering rates arising from the interactions of electrons with bulk longitudinal optical (LO) phonon modes in a hollow cylinder are calculated as functions of the inner radius and the uniform axial applied magnetic field. Now, the specific nature of electron-phonon interactions mainly depends on the character of the energy spectrum of electrons. As is well known, in cylindrical quantum wires, the application of a parallel magnetic field lifts the double degeneracy of the non-zero azimuthal quantum number states; m≠0; irrespective of all electron's radial quantum number l states. In fact, this Zeeman splitting is such that the m < 0 electron's energy subbands initially decrease with the increase of the parallel applied magnetic field. In a solid cylinder, the lowest-order; {l = 1; m = 0} subband is always the ground state. In a hollow cylinder, however, as the axial applied magnetic field is increased, the electron's energy subbands take turns at becoming the ground state; following the sequence {m=0,-1,-2...-N} of azimuthal quantum numbers. Furthermore, in a hollow cylinder, in general, the electron's energy separations between any two subbands are less than the LO phonon energy except for exceptionally high magnetic fields, and some highest-order quantum number states. In view of this, the discussion of the energy relaxation here is focused mainly on intrasubband scattering of electrons and only within the lowest-order {l = 1; m = 0} electron's energy subband. The intrasubband scattering rates are found to be characterized by shallow minima in their variations with the inner radius, again, for a fixed outer radius. This feature is a consequence of a balance between two seemingly conflicting effects of the electron's confinement by the inner and outer walls of the hollow cylinder. First; increased confinement of the charge carriers generally leads to the enhancement of the rates. Second; the presence of a hole in a hollow cylinder leads to a significant suppression of the scattering rates. The intrasubband scattering rates also show a somewhat parabolic increase in their variations with the applied magnetic field; an increase which is more pronounced in a relatively thick hollow cylinder.

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Quantum confinement of coherent acoustic phonons in transferred single-crystalline bismuth nanofilms

Cited by 6 publications

References 46 publications

Inducing thermodynamically blocked atomic ordering via strongly driven nonequilibrium kinetics

Inducing thermodynamically blocked atomic ordering via strongly driven nonequilibrium kinetics

Ultrafast Generation of Coherent Phonons in Two-Dimensional Bismuthene

Electron-LO-phonon Intrasubband Scattering Rates in a Hollow Cylinder Under the Influence of a Uniform Axial Applied Magnetic Field

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