Showing 24 results for Author: Chengyun Hua
Nov, 2023
Journal
New pathways to controlling the morphology of superconducting vortex lattices─and their subsequent dynamics─are required to guide and scale vortex world-lines into a computing platform. We have found that the nematic twin boundaries align superconducting vortices in the adjacent terraces due to the incommensurate potential between vortices surrounding twin boundaries and t…
Nov, 2023
Journal
Superconducting nanowire single-photon detectors (SNSPDs) offer high-quantum-efficiency and low-dark-count-rate single-photon detection. In a growing number of cases, large magnetic fields are being incorporated into quantum microscopes, nanophotonic devices, and sensors for nuclear and high-energy physics that rely on SNSPDs, but superconducting devices generally perform…
Nov, 2023
Journal
Topological quantum computation based on Majorana bound states may enable new paths to fault-tolerant quantum computing. Several recent experiments have suggested that the vortex cores of topological superconductors, such as iron-based superconductors, may host Majorana bound states at zero energy. However, quantum computation with these zero-energy vortex bound states req…
Nov, 2023
Journal
Nonlocal thermal transport is generally described by the Peierls-Boltzmann transport equation (PBE). However, solving the PBE for a general space-time dependent problem remains a challenging task due to the high dimensionality of the integro-differential equation. In this work, we present a direct solution to the space-time dependent PBE with a linearized collision matrix…
Nov, 2023
Book Chapter
Chapter 6 reviews the current status of resolving the phonon mean free path distribution in real materials from both the computational and experimental perspectives, which is essential for engineering materials at the nanoscale to achieve desirable thermal transport properties.
Nov, 2023
Journal
Lead halide perovskites are strong candidates for high-performance low-cost photovoltaics, light emission, and detection applications. A hot-phonon bottleneck effect significantly extends the cooling time of hot charge carriers, which thermalize through carrier–optic phonon scattering, followed by optic phonon decay to acoustic phonons and finally thermal conduction. To un…
Nov, 2023
Journal
Phonon heat conduction over length scales comparable to their mean free paths is a topic of considerable interest for basic science and thermal management technologies. However, debate exists over the appropriate constitutive law that defines thermal conductivity in the nondiffusive regime. Here, we derive a generalized Fourier's law that links the heat flux and temperatur…
Nov, 2023
Journal
The coupling of lattice dynamics and phonon transport methodologies with density functional theory has become a powerful tool for calculating lattice thermal conductivity (κ) with demonstrated quantitative accuracy and applicability to a wide range of materials. More importantly, these first-principles transport methods lack empirical tuning parameters so that reliable pre…
Nov, 2023
Journal
Examples of single-crystal epitaxial thin films of a high entropy perovskite oxide are synthesized. Pulsed laser deposition is used to grow the configurationally disordered ABO3 perovskite Ba(Zr0.2Sn0.2Ti0.2Hf0.2Nb0.2)O3 epitaxially on SrTiO3 and MgO substrates. X-ray diffraction and scanning transmission electron microscopy demonstrate that the films are single phase with…
Nov, 2023
Journal
Quasiballistic heat conduction, in which some phonons propagate ballistically over a thermal gradient, has recently become of intense interest. Most works report that the thermal resistance associated with nanoscale heat sources is far larger than predicted by Fourier's law; however, recent experiments show that in certain cases the difference is negligible despite the hea…
Nov, 2023
Journal
Quasiballistic heat conduction from nanoscale heat sources of size comparable to phonon mean free paths has recently become of intense interest both scientifically and for its applications. Prior work has established that, in the quasiballistic regime, the apparent thermal properties of materials depend both on intrinsic mechanisms and the characteristics of the applied th…