Classical molecular dynamics(MD)simulations ae performed to investigate the effects of mechanical strain on the thermal conductivity of single-layer black phosphorus(SLBP)nanoribbons along different directions at room...Classical molecular dynamics(MD)simulations ae performed to investigate the effects of mechanical strain on the thermal conductivity of single-layer black phosphorus(SLBP)nanoribbons along different directions at room temperature.The results show that the tensile strain afects the thermal conductivity of nanoribbons by changing thephonon density of state(DOS)and mean free path(M FP).The thermal conductivity shows a sharp enhancement with the tensile strain applied along the armchai diection,while it increases slowly with the strain applied along the zigzag diection.This phenomenon cm be mainly explained by effects of the phonon DOS and MFP.The increasing strain along the armchai direction weakens DOS and strengthens MFP clearly.However,when it comes to the increasing strain along the zigzag deection'DOS enliances significantly while MFP decreases slightly.The findings explore the relationship between the tensile strain and the thermal conductivity reasonably and can provide a reliable method to estimate the MFP of black phosphorus.展开更多
Developing an understanding of the physics underlying vibrational phonon modes,which are strongly related to thermal transport,has attracted significant research interest.Herein,we report the successful synthesis of b...Developing an understanding of the physics underlying vibrational phonon modes,which are strongly related to thermal transport,has attracted significant research interest.Herein,we report the successful synthesis of bulk SbCrSe_(3)single crystal and its thermal transport property over the temperature range from 2 to 300 K.Using angle-resolved polarized Raman spectroscopy(ARPRS)and group theory calculation,the vibrational symmetry of each observed Raman mode in the cleaved(001)crystal plane of SbCrSe_(3)is identified for the first time,and then further verified through firstprinciples calculations.The ARPRS results of some Raman modes(e.g.,Ag2~64 cm-1 and Ag 7~185 cm-1)can be adopted to determine the crystalline orientation.More importantly,the temperature dependence of the lattice thermal conductivity(κL)is revealed to be more accurately depicted by the three-phonon scattering processes throughout the measured temperature range,substantiated by in-situ Raman spectroscopy analysis and the model-predictedκL.These results reveal the fundamental physics of thermal transport for SbCrSe_(3)from a completely new perspective and should thus ignite research interest in the thermal properties of other lowdimensional materials using the same strategy.展开更多
Searching and designing materials with intrinsically low lattice thermal conductivity （LTC） have attracted extensive considera- tion in thermoelectrics and thermal management community. The concept of part-crystalli...Searching and designing materials with intrinsically low lattice thermal conductivity （LTC） have attracted extensive considera- tion in thermoelectrics and thermal management community. The concept of part-crystalline part-liquid state, or even part-crystalline part-amorphous state, has recently been proposed to describe the exotic structure of materials with chemical-bond hierarchy, in which a set of atoms is weakly bonded to the rest species while the other sublattices retain relatively strong rigidity. The whole system inherently manifests the coexistence of rigid crystalline sublattices and fluctuating noncrystalline substructures. Representative materials in the unusual state can be classified into two categories, i.e., caged and non-caged ones. LTCs in both systems deviate from the traditional 7-1 relationship （T, the absolute temperature）, which can hardly be described by small-parameter-based perturbation approaches. Beyond the classical perturbation theory, an extra rattling-like scattering should be considered to interpret the liquid-like and sublattice-amorphization-induced heat transport. Such a kind of compounds could be promising high-performance thermoelectric materials, due to the extremely low LTCs. Other physical properties for these part-crystalline substances should also exhibit certain novelty and deserve further exploration.展开更多
基金The National Natural Science Foundation of China(No.51575104)
文摘Classical molecular dynamics(MD)simulations ae performed to investigate the effects of mechanical strain on the thermal conductivity of single-layer black phosphorus(SLBP)nanoribbons along different directions at room temperature.The results show that the tensile strain afects the thermal conductivity of nanoribbons by changing thephonon density of state(DOS)and mean free path(M FP).The thermal conductivity shows a sharp enhancement with the tensile strain applied along the armchai diection,while it increases slowly with the strain applied along the zigzag diection.This phenomenon cm be mainly explained by effects of the phonon DOS and MFP.The increasing strain along the armchai direction weakens DOS and strengthens MFP clearly.However,when it comes to the increasing strain along the zigzag deection'DOS enliances significantly while MFP decreases slightly.The findings explore the relationship between the tensile strain and the thermal conductivity reasonably and can provide a reliable method to estimate the MFP of black phosphorus.
基金the National Natural Science Foundation of China(11904348,11604032,51772035,51672270 and 52071041)the Fundamental Research Funds for the Central Universities(106112016CDJZR308808)。
文摘Developing an understanding of the physics underlying vibrational phonon modes,which are strongly related to thermal transport,has attracted significant research interest.Herein,we report the successful synthesis of bulk SbCrSe_(3)single crystal and its thermal transport property over the temperature range from 2 to 300 K.Using angle-resolved polarized Raman spectroscopy(ARPRS)and group theory calculation,the vibrational symmetry of each observed Raman mode in the cleaved(001)crystal plane of SbCrSe_(3)is identified for the first time,and then further verified through firstprinciples calculations.The ARPRS results of some Raman modes(e.g.,Ag2~64 cm-1 and Ag 7~185 cm-1)can be adopted to determine the crystalline orientation.More importantly,the temperature dependence of the lattice thermal conductivity(κL)is revealed to be more accurately depicted by the three-phonon scattering processes throughout the measured temperature range,substantiated by in-situ Raman spectroscopy analysis and the model-predictedκL.These results reveal the fundamental physics of thermal transport for SbCrSe_(3)from a completely new perspective and should thus ignite research interest in the thermal properties of other lowdimensional materials using the same strategy.
基金the National Key Basic Research Program of China(Grant No.2013CB632501)the National Natural Science Foundation of China(Grant Nos.11234012+1 种基金51121064 and 51572167)the Science and Technology Commission of Shanghai Municipality(Grant Nos.14DZ2261200 and 15JC1400301)
文摘Searching and designing materials with intrinsically low lattice thermal conductivity （LTC） have attracted extensive considera- tion in thermoelectrics and thermal management community. The concept of part-crystalline part-liquid state, or even part-crystalline part-amorphous state, has recently been proposed to describe the exotic structure of materials with chemical-bond hierarchy, in which a set of atoms is weakly bonded to the rest species while the other sublattices retain relatively strong rigidity. The whole system inherently manifests the coexistence of rigid crystalline sublattices and fluctuating noncrystalline substructures. Representative materials in the unusual state can be classified into two categories, i.e., caged and non-caged ones. LTCs in both systems deviate from the traditional 7-1 relationship （T, the absolute temperature）, which can hardly be described by small-parameter-based perturbation approaches. Beyond the classical perturbation theory, an extra rattling-like scattering should be considered to interpret the liquid-like and sublattice-amorphization-induced heat transport. Such a kind of compounds could be promising high-performance thermoelectric materials, due to the extremely low LTCs. Other physical properties for these part-crystalline substances should also exhibit certain novelty and deserve further exploration.
