论文标题
非本地电导率对石墨烯片之间近场辐射传热的影响
The Effect of Non-Local Electrical Conductivity on Near-Field Radiative Heat Transfer between Graphene Sheets
论文作者
论文摘要
石墨烯的近场辐射传热是根据其电导率确定的，通常使用局部库博和drude公式建模。在这封信中，我们使用Lindhard模型与Mermin弛豫时间近似结合使用了石墨烯电导率的非本地性。我们还研究了与波形电导率的变化如何影响两个被真空间隙隔开的石墨烯片之间的近场辐射电导。结果表明，$ k_p $ $k_ρ$ s的电导率变化大于$ 100K_0 $，其中$ k_0 $是自由空间中波德向量的大小。 Kubo电导率提供了两个石墨烯片之间的光谱辐射电导的准确估算，除了地石墨烯的表面 - 平价频率周围，在分离间隙差距大于20 nm的分离间隙，而该模式的贡献$ k_p> 100k_0 $ to radiatiative电导率。事实证明，Drude配方对于对石墨烯的电导率和辐射电导进行建模是不准确的，除了在低于费米温度的温度下，频率大于$2μ_c/{\ hbar} $，其中$μ_c$ and $μ_c$ and $ {\ hbar} $是化学电位和不变的plance planc的plance planc。还表明，应在Lindhard模型中正确考虑电子散射过程，以便保守局部电子数。在无碰撞的Lindhard模型中，$ω$的替换为$ω+Iγ$（$ω$，$ i $和$γ$分别为角度频率，想象的单位和散射率），在计算Chumente Chuperene电导率和放射性电导率和辐射功能中的重大错误中的局部电子数和结果都无法满足局部电子数量和结果。
Graphene's near-field radiative heat transfer is determined from its electrical conductivity, commonly modeled using the local Kubo and Drude formulas. In this letter, we analyze the non-locality of graphene's electrical conductivity using the Lindhard model combined with the Mermin relaxation time approximation. We also study how the variation of electrical conductivity with wavevector affects near-field radiative conductance between two graphene sheets separated by a vacuum gap. It is shown that the variation of electrical conductivity with wavevector, $k_ρ$, is appreciable for $k_ρ$s greater than $100k_0$, where $k_0$ is the magnitude of the wavevector in the free space. The Kubo electrical conductivity provides an accurate estimation of the spectral radiative conductance between two graphene sheets except for around the surface-plasmon-polariton frequency of graphene and at separation gaps smaller than 20 nm where there is a non-negligible contribution from modes with $k_ρ>100k_0$ to the radiative conductance. The Drude formula proves to be inaccurate for modeling the electrical conductivity and radiative conductance of graphene except for at temperatures much below the Fermi temperature and frequencies much smaller than $2μ_c/{\hbar}$, where $μ_c$ and ${\hbar}$ are the chemical potential and reduced Planck's constant, respectively. It is also shown that the electronic scattering processes should be considered in the Lindhard model properly, such that the local electron number is conserved. A substitution of $ω$ by $ω+iγ$ ($ω$, $i$, and $γ$ being the angular frequency, imaginary unit, and scattering rate, respectively) in the collisionless Lindhard model does not satisfy the conservation of the local electron number and results in significant errors in computing graphene's electrical conductivity and radiative conductance.
