Understanding how structural disorder affects phonon transport is critical for controlling thermal conduction in nanoscale materials.In this work,we investigate thermal transport in Si-like nanowires composed of layer...Understanding how structural disorder affects phonon transport is critical for controlling thermal conduction in nanoscale materials.In this work,we investigate thermal transport in Si-like nanowires composed of layered atoms with one-dimensional correlated disorder.Using the nonequilibrium Green’s function method,we reveal that introducing correlation among atomic layers induces phonon Anderson localization at low-frequencies,leading to a nonmonotonic length dependence of thermal conductivity:it increases at short lengths but decreases beyond a critical size,in sharp contrast to the monotonic trend observed in random disorder.Despite having fewer mass interfaces,the correlated nanowires exhibit lower thermal conductivity than their random disorder counterparts when the nanowire length exceeds 70 nm.Frequency-resolved analysis shows that spatial correlation suppresses the transmission of low-frequency phonons and promotes their localization,while concurrently extending the localization length of mid-and high-frequency modes.This selective reshaping of phonon localization is responsible for the anomalous transport behavior.Our findings provide new insights into heat transport engineering via tailored disorder in low-dimensional materials.展开更多
Inspired by the recent discovery of breathing kagome materials Nb_(3)Cl_(8) and Nb_(3)TeCl_(7),we have explored the influence of the breathing effect on the Hubbard model of the kagome lattice.Utilizing the determinan...Inspired by the recent discovery of breathing kagome materials Nb_(3)Cl_(8) and Nb_(3)TeCl_(7),we have explored the influence of the breathing effect on the Hubbard model of the kagome lattice.Utilizing the determinant quantum Monte Carlo method,we first investigated the average sign problem in the breathing kagome lattice,which is influenced by both the breathing strength and the interaction strength.Secondly,we calculated the electronic kinetic energy,the direct current conductivity,and the electronic density of states at the Fermi level to determine the critical interaction strength for the metal-insulator transition.Our results indicate that the breathing effect,in conjunction with the interaction strength,drives the kagome system from a metal to an insulator.Finally,we evaluated the magnetic properties and constructed a phase diagram incorporating both transport and magnetic properties.The phase diagram reveals that as the interaction strength increases,the system transitions from a paramagnetic metal to a Mott insulator.Our research provides theoretical guidance for utilizing the breathing effect to control the band gaps,conductivity,and magnetic properties of kagome materials with electronic interactions.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20210,52576070 for H.Y.and 12174276 for S.X.)+1 种基金the Basic and Applied Basic Research Foundation of Guangdong Province(Grant No.2024A1515010521 for S.X.)the China Scholarship Council(CSC)(Grant No.202406120152 for W.Z.)。
文摘Understanding how structural disorder affects phonon transport is critical for controlling thermal conduction in nanoscale materials.In this work,we investigate thermal transport in Si-like nanowires composed of layered atoms with one-dimensional correlated disorder.Using the nonequilibrium Green’s function method,we reveal that introducing correlation among atomic layers induces phonon Anderson localization at low-frequencies,leading to a nonmonotonic length dependence of thermal conductivity:it increases at short lengths but decreases beyond a critical size,in sharp contrast to the monotonic trend observed in random disorder.Despite having fewer mass interfaces,the correlated nanowires exhibit lower thermal conductivity than their random disorder counterparts when the nanowire length exceeds 70 nm.Frequency-resolved analysis shows that spatial correlation suppresses the transmission of low-frequency phonons and promotes their localization,while concurrently extending the localization length of mid-and high-frequency modes.This selective reshaping of phonon localization is responsible for the anomalous transport behavior.Our findings provide new insights into heat transport engineering via tailored disorder in low-dimensional materials.
基金supported by the National Science Foundation of China(Grant No.12474218)Beijing Natural Science Foundation(Grant Nos.1242022 and 1252022).
文摘Inspired by the recent discovery of breathing kagome materials Nb_(3)Cl_(8) and Nb_(3)TeCl_(7),we have explored the influence of the breathing effect on the Hubbard model of the kagome lattice.Utilizing the determinant quantum Monte Carlo method,we first investigated the average sign problem in the breathing kagome lattice,which is influenced by both the breathing strength and the interaction strength.Secondly,we calculated the electronic kinetic energy,the direct current conductivity,and the electronic density of states at the Fermi level to determine the critical interaction strength for the metal-insulator transition.Our results indicate that the breathing effect,in conjunction with the interaction strength,drives the kagome system from a metal to an insulator.Finally,we evaluated the magnetic properties and constructed a phase diagram incorporating both transport and magnetic properties.The phase diagram reveals that as the interaction strength increases,the system transitions from a paramagnetic metal to a Mott insulator.Our research provides theoretical guidance for utilizing the breathing effect to control the band gaps,conductivity,and magnetic properties of kagome materials with electronic interactions.
