<?xml version='1.0' encoding='utf-8'?> <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> <dc:creator>Luo, Yixiu</dc:creator> <dc:creator>Yang, Xiaolong</dc:creator> <dc:creator>Feng, Tianli</dc:creator> <dc:creator>Wang, Jingyang</dc:creator> <dc:creator>Ruan, Xiulin</dc:creator> <dc:date>2020-04-11</dc:date> <dc:description>Many low-thermal-conductivity (κL) crystals show intriguing temperature (T) dependence of κL: κL∝T-1 (crystal-like) at intermediate temperatures whereas weak T-dependence (glass-like) at high temperatures. It has been in debate whether thermal transport can still be described by phonons at the Ioffe-Regel limit. In this work, we propose that most phonons are still well defined for thermal transport, whereas they carry heat via dual channels: “normal” phonons described by the Boltzmann transport equation theory and “diffuson-like” phonons described by the diffusion theory. Three physics-based criteria are incorporated into first-principles calculations to judge mode-by-mode between the two phonon channels. Case studies on La2Zr2O7 and Tl3VSe4 show that normal phonons dominate low temperatures while diffuson-like phonons dominate high temperatures. Our present dual-phonon theory enlightens the physics of hierarchical phonon transport as approaching the Ioffe-Regel limit, and provides a numerical method that should be practically applicable to many materials with vibrational hierarchy. </dc:description> <dc:identifier>https://archive.materialscloud.org/record/2020.0036/v1</dc:identifier> <dc:identifier>doi:10.24435/materialscloud:2020.0036/v1</dc:identifier> <dc:identifier>mcid:2020.0036/v1</dc:identifier> <dc:identifier>oai:materialscloud.org:361</dc:identifier> <dc:language>en</dc:language> <dc:publisher>Materials Cloud</dc:publisher> <dc:rights>info:eu-repo/semantics/openAccess</dc:rights> <dc:rights>Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode</dc:rights> <dc:subject>Dual-phonon theory</dc:subject> <dc:subject>thermal conductivity</dc:subject> <dc:subject>theoretical calculation</dc:subject> <dc:title>Vibrational hierarchy leads to dual-phonon transport in low thermal conductivity crystals</dc:title> <dc:type>Dataset</dc:type> </oai_dc:dc>