Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional...Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional ferromagnetic honeycomb structure of group-Ⅳ elements including silicene, germanene and stanene within the Green's function approach. We also find these quantities in the presence of applied external electric field. Our results show that the silicene(stanene) has the maximum(minimum) heat capacity and magnetic susceptibility at uniform electric fields. From the behavior of theses quantities, the band gap has been changed with impurity concentration, impurity scattering strength and electric field. The analysis on the impurity-dependent magnetic susceptibility curves shows a phase transition from ferromagnetic to paramagnetic and antiferromagnetic phases. Interestingly, electronic heat capacity increases(decreases) with impurity concentration in silicene(germanene and stanene) structure.展开更多
Phase change materials(PCM)have evolved over time and gradually adapted to the emerging needs of society.Their excellent properties,such as high latent heat storage capacity and fast response time,have aroused tremend...Phase change materials(PCM)have evolved over time and gradually adapted to the emerging needs of society.Their excellent properties,such as high latent heat storage capacity and fast response time,have aroused tremendous interest in applications such as thermal management systems,building energy efficiency,communications,and power.However,drawbacks such as low thermal conductivity,susceptibility to leakage,and small latent heat of phase transition limit the practical application of PCM.In this work,an innovative wood derived carbon-carbon nanotubes-paraffin wax(WDC-CNTs-PW)phase change energy storage composite is prepared by the high-temperature carbonization process,injection chemical vapor deposition,and vacuum impregnation method.The enhanced thermal conductivity of WDC-CNTs-PW is mainly due to the three-dimensional porous structure of WDC and the homogeneous introduction of the thermally enhanced filler CNTs.The axial and radial thermal conductivities of WDC-CNTs-PW are 0.35 and 0.29 W·m^(-1)·K^(-1),respectively.The enthalpies of melting and crystallization of WDC-CNTs-PW are 142.02 and 136.14 J·g^(-1),respectively,with impregnation efficiency of 70.95% and loading ratio of 73.01%.With excellent thermal conductivity,latent heat of phase transition,and encapsulation property,WDC-CNTs-PW opens up a surprising strategy for PCM applications in areas such as high technology microelectronics and energy-saving in houses.展开更多
文摘Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional ferromagnetic honeycomb structure of group-Ⅳ elements including silicene, germanene and stanene within the Green's function approach. We also find these quantities in the presence of applied external electric field. Our results show that the silicene(stanene) has the maximum(minimum) heat capacity and magnetic susceptibility at uniform electric fields. From the behavior of theses quantities, the band gap has been changed with impurity concentration, impurity scattering strength and electric field. The analysis on the impurity-dependent magnetic susceptibility curves shows a phase transition from ferromagnetic to paramagnetic and antiferromagnetic phases. Interestingly, electronic heat capacity increases(decreases) with impurity concentration in silicene(germanene and stanene) structure.
基金supported by the Key R&D Program of Shaanxi Province(No.2021ZDLGY14-04)the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.XN2022023)the Joint Funds of the National Natural Science Foundation of China(No.U21B2067).
文摘Phase change materials(PCM)have evolved over time and gradually adapted to the emerging needs of society.Their excellent properties,such as high latent heat storage capacity and fast response time,have aroused tremendous interest in applications such as thermal management systems,building energy efficiency,communications,and power.However,drawbacks such as low thermal conductivity,susceptibility to leakage,and small latent heat of phase transition limit the practical application of PCM.In this work,an innovative wood derived carbon-carbon nanotubes-paraffin wax(WDC-CNTs-PW)phase change energy storage composite is prepared by the high-temperature carbonization process,injection chemical vapor deposition,and vacuum impregnation method.The enhanced thermal conductivity of WDC-CNTs-PW is mainly due to the three-dimensional porous structure of WDC and the homogeneous introduction of the thermally enhanced filler CNTs.The axial and radial thermal conductivities of WDC-CNTs-PW are 0.35 and 0.29 W·m^(-1)·K^(-1),respectively.The enthalpies of melting and crystallization of WDC-CNTs-PW are 142.02 and 136.14 J·g^(-1),respectively,with impregnation efficiency of 70.95% and loading ratio of 73.01%.With excellent thermal conductivity,latent heat of phase transition,and encapsulation property,WDC-CNTs-PW opens up a surprising strategy for PCM applications in areas such as high technology microelectronics and energy-saving in houses.
