Review
Physics, Condensed Matter
S. L. Prischepa, V. N. Kushnir
Summary: This article discusses various aspects of phonon spectrum changes in nanostructured phonon-mediated superconductors. With the development of experimental techniques and the acquisition of new results, the understanding of the influence of surface and nanoscale on the electron-phonon interaction and critical temperature T (c) has changed and deepened. The article is divided into ten parts, discussing superconductivity theory, properties of nanostructured thin films, phonon spectrum modifications, and light excitation of superconducting materials, among others.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Materials Science, Multidisciplinary
Xin Liang, Hemeng Wang, Changan Wang
Summary: The study reveals a strong electron-phonon interaction in group IV and V transition metal carbides, leading to an anomalous weak temperature dependence of lattice thermal conductivity. It also shows that strong electron-phonon interaction can notably suppress lattice thermal transport without the necessity of Fermi surface nesting.
Article
Multidisciplinary Sciences
Ruishi Qi, Ruochen Shi, Yuehui Li, Yuanwei Sun, Mei Wu, Ning Li, Jinlong Du, Kaihui Liu, Chunlin Chen, Ji Chen, Feng Wang, Dapeng Yu, En-Ge Wang, Peng Gao
Summary: Four-dimensional electron energy-loss spectroscopy measurements reveal localized modes at heterointerfaces that impact thermal conductance and electron mobility. Experimental challenges stem from the need to achieve combined spatial, momentum, and spectral resolutions to probe these modes effectively.
Article
Chemistry, Multidisciplinary
Wenjie Hao, Minghui Gu, Zhenyun Tian, Shaohua Fu, Meng Meng, Hong Zhang, Jiandong Guo, Jimin Zhao
Summary: By employing ultrafast spectroscopy, this study uncovers the spatial separation between electron-phonon coupling (EPC) and phonon-phonon scattering (PPS), providing a vital foundation for designing future quantum nano devices.
Article
Materials Science, Multidisciplinary
S. Sakamoto, N. Gauthier, P. S. Kirchmann, J. A. Sobota, Z. -X. Shen
Summary: In this study, time- and angle-resolved photoemission spectroscopy (trARPES) measurements were conducted on the Sb(111) surface. The results showed band- and momentum-dependent binding-energy oscillations in the bulk and surface bands, which were driven by A(1g) and E-g coherent phonons. Frozen-phonon calculations based on density functional theory successfully reproduced the observed behavior, providing evidence for the connection between electron-phonon coupling and coherent binding-energy dynamics tied to lattice vibration. This study confirms that trARPES can probe band-, momentum-, and mode-dependent electron-phonon coupling in the low fluence limit.
Article
Physics, Condensed Matter
Kavita Yadav, Saurabh Singh, Omprakash Muthuswamy, Tsunehiro Takeuchi, K. Mukherjee
Summary: Insights into the scattering mechanisms responsible for the reduction in lattice thermal conductivity in half-Heusler alloys are crucial. In this study, the temperature response of thermal conductivity of ZrCo1-xIr xSb alloys was thoroughly investigated. The results showed that partial substitution of the heavier element Ir effectively reduced the thermal conductivity of n-type ZrCoSb by softening the acoustic phonon modes and inducing point defect scattering. The lowest reported thermal conductivity value for n-type Zr-based HHA was achieved in ZrCo0.9Ir0.1Sb.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Multidisciplinary Sciences
Feifan Wang, Weibin Chu, Lucas Huber, Teng Tu, Yanan Dai, Jue Wang, Hailin Peng, Jin Zhao, X. -Y. Zhu
Summary: Recent mechanistic studies have proposed the ferroelectric large polaron proposal as an explanation for efficient charge carrier screening in lead halide perovskites (LHPs). However, it remains unclear whether this proposal applies to semiconductors with LHP-like anharmonic and dynamically disordered phonons. In this study, we investigate electron-phonon coupling in Bi2O2Se, a semiconductor with similarities to LHPs. Our findings suggest that the strong coupling of an anharmonic phonon mode to photo-excited charge carriers is a result of symmetry-lowering in polaron formation. This study provides insights into charge interaction with anharmonic phonons and suggests that ferroelectric polaron formation may be a general principle for efficient charge carrier screening and for defect-tolerant semiconductors.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Condensed Matter
Ramji Singh, Mitra Dutta, Michael A. Stroscio
Summary: It is well known that in many polar materials, carrier-optical-phonon scattering rates dominate over carrier-acoustic-phonon scattering rates. The large Frohlich coupling constants in these materials lead to substantial corrections to the Fermi golden rule scattering rates. Corrections to the Fermi golden rule reported have widespread impact on carrier transport for materials with large Frohlich coupling constants.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Multidisciplinary Sciences
Mir Mohammad Sadeghi, Yajie Huang, Chao Lian, Feliciano Giustino, Emanuel Tutuc, Allan H. MacDonald, Takashi Taniguchi, Kenji Watanabe, Li Shi
Summary: The peculiar electron-phonon interaction in graphene heterostructures enables ultrahigh mobility, electron hydrodynamics, superconductivity, and superfluidity. A peak in the Lorenz ratio near 60 kelvin and its decrease with increased mobility are observed in degenerate graphene, indicating an unusual behavior. This experimental observation, combined with ab initio calculations and analytical models, suggests that broken reflection symmetry in graphene heterostructures can relax the selection rule for electron coupling with flexural phonons, contributing to the increase of the Lorenz ratio at intermediate temperatures.
Article
Physics, Condensed Matter
Shoubhik Mandal, Debarghya Mallick, Yugandhar Bitla, R. Ganesan, P. S. Anil Kumar
Summary: Recently, it has been shown that Bi1Te1 is a dual topological insulator with both quasi-1D surface states and topological crystalline insulating surface states. Moreover, Bi1Te1 is predicted to be a higher order topological insulator. However, experimental studies on the Bi1Te1 single crystal and its doping effects are lacking. In this study, magneto-transport measurements were performed on exfoliated microflakes and Sb-doped Bi1Te1 single crystals. The results revealed the presence of decoupled topological surface states and provided insights into the thickness-dependent dephasing mechanism and the strength of bulk-surface coupling.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Review
Physics, Applied
Gang Chen
Summary: Phonon heat conduction at the microscale and nanoscale exhibits complex phenomena beyond the traditional predictions of Fourier's law, attracting wide attention. The development in studying phonon heat conduction phenomena reveals that besides classical size effects, other novel phenomena have emerged, often occurring at microscale and nanoscale, or only at elevated temperatures.
NATURE REVIEWS PHYSICS
(2021)
Article
Physics, Multidisciplinary
M-A Carmona-Galvan, R. Heid, O. De la Pena-Seaman
Summary: This study investigates the lattice dynamics, electron-phonon coupling, and superconducting properties of alpha-MoB2 under applied pressure. The results show that the phonon modes along specific high-symmetry paths contribute significantly to the electron-phonon coupling constant. The acoustic low-frequency modes dominate the coupling, and at a pressure of 90 GPa, the superconducting critical temperature is in agreement with experimental observations. Further increase in pressure leads to a decrease in Tc, correlated with changes in the acoustic low-frequency phonon modes and electron-phonon coupling parameter.
Article
Chemistry, Multidisciplinary
Benedikt Haas, Tara M. Boland, Christian Elsaesser, Arunima K. Singh, Katia March, Juri Barthel, Christoph T. Koch, Peter Rez
Summary: Phonon scattering at grain boundaries plays a crucial role in controlling the thermal conductivity of nanoscale devices. This study uses monochromated electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) to measure the 60 meV optic mode at grain boundaries in silicon at atomic resolution. The results show the existence of localized phonon modes and support the idea that grain boundaries can act as waveguides.
Article
Nanoscience & Nanotechnology
Christopher R. R. Gubbin, Simone De Liberato
Summary: In this work, we propose an alternative method to generate mid-infrared light by utilizing the nonlocal optical response of nanoscopic polar dielectric crystals. By coupling longitudinal phonons with electrical currents, longitudinal-transverse polaritons can be efficiently generated, leading to resonant narrowband photonic emission.
Article
Physics, Applied
Yuya Kubota, Yoshikazu Tanaka, Tadashi Togashi, Tomio Ebisu, Kenji Tamasaku, Hitoshi Osawa, Tetsuya Wada, Osamu Sugino, Iwao Matsuda, Makina Yabashi
Summary: The ultrafast atomic motion of a photo-induced coherent phonon of bismuth at low temperatures was directly observed using time-resolved x-ray diffraction. A cryostat transparent to both optical lasers and x-rays enabled versatile diffraction measurements in a wide temperature range, including temperatures below 10 K. It was found that the atomic displacement in the fully symmetric A(1g) phonon mode is suppressed at low temperatures, suggesting a suppression of the displacive excitation process in phonon generation with decreasing temperature.
APPLIED PHYSICS LETTERS
(2023)
