In this Letter, we report measurements of the coupling between Dirac fermion quasiparticles (DFQs) and phonons on the (001) surface of the strong topological insulator Bi2Se3. While most contemporary investigations of this coupling have involved examining the temperature dependence of the DFQ self-energy via angle-resolved photoemission spectroscopy measurements, we employ inelastic helium-atom scattering to explore, for the first time, this coupling from the phonon perspective. Using a Hilbert transform, we are able to obtain the imaginary part of the phonon self-energy associated with a dispersive surface-phonon branch identified in our previous work [Phys. Rev. Lett. 107, 186102 (2011)] as having strong interactions with the DFQs. From this imaginary part of the self-energy we obtain a branch-specific electron-phonon coupling constant of 0.43, which is stronger than the values reported from the angle-resolved photoemission spectroscopy measurements.
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http://dx.doi.org/10.1103/PhysRevLett.108.185501 | DOI Listing |
J Phys Chem Lett
January 2025
Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain.
So far, the striking sign reversal in the near-ambient slope of the gap temperature dependence of colloidal CsPbCl perovskite nanocrystals (NCs) compared to its Br counterpart remains unresolved. Pure bromide NCs exhibit a linear gap increase with increasing temperature, to which thermal expansion and electron-phonon interaction equally contribute. In contrast, the temperature slope for the chlorine compound gap is clearly negative.
View Article and Find Full Text PDFPNAS Nexus
January 2025
The Harrison M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040, USA.
The direct, ultrafast excitation of polar phonons with electromagnetic radiation is a potent strategy for controlling the properties of a wide range of materials, particularly in the context of influencing their magnetic behavior. Here, we show that, contrary to common perception, the origin of phonon-induced magnetic activity does not stem from the Maxwellian fields resulting from the motion of the ions themselves or the effect their motion exerts on the electron subsystem. Through the mechanism of electron-phonon coupling, a coherent state of circularly polarized phonons generates substantial non-Maxwellian fields that disrupt time-reversal symmetry, effectively emulating the behavior of authentic magnetic fields.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072, P. R. China.
Mn ions doped CsPbCl perovskite nanocrystals (NCs) exhibit superiority of spin-associated optical and electrical properties. However, precisely controlling the doping concentration, doping location, and the mono-distribution of Mn ions in the large-micro-size CsPbCl perovskite host is a formidable challenge. Here, the micro size CsPbCl perovskite crystals (MCs) are reported with uniform Mn ions doping by self-assembly of Mn ions doped CsPbCl perovskite NCs.
View Article and Find Full Text PDFNat Commun
January 2025
Institute of Biomedical Engineering, College of Life Sciences, Qingdao University, Qingdao, China.
The development of acid-stable water oxidation electrocatalysts is crucial for high-performance energy conversion devices. Different from traditional nanostructuring, here we employ an innovative microwave-mediated electron-phonon coupling technique to assemble specific Ru atomic patterns (instead of random Ru-particle depositions) on MnCrO surfaces (Ru-MnCrO) in RuCl solution because hydrated Ru-ion complexes can be uniformly activated to replace some Mn sites at nearby Cr-dopants through microwave-triggered energy coherent superposition with molecular rotations and collisions. This selective rearrangement in Ru-MnCrO with particular spin-differentiated polarizations can induce localized spin domain inversion from reversed to parallel direction, which makes Ru-MnCrO demonstrate a high current density of 1.
View Article and Find Full Text PDFNanoscale Adv
December 2024
Department of Biological Sciences and Engineering, Indian Institute of Technology Palakkad Palakkad Kerala 678 623 India.
Since the initial publication on the first TiCT MXene in 2011, there has been a significant increase in the number of reports on applications of MXenes in various domains. MXenes have emerged as highly promising materials for various biomedical applications, including photothermal therapy (PTT), drug delivery, diagnostic imaging, and biosensing, owing to their fascinating conductivity, mechanical strength, biocompatibility and hydrophilicity. Through surface modification, MXenes can mitigate cytotoxicity, enhance biological stability, and improve histocompatibility, thereby enabling their potential use in biomedical applications.
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