论文标题
洛伦兹的数量和电子热电图：热力学和直接DFT计算
Lorenz Number and Electronic Thermoelectric Figure of Merit: Thermodynamics and Direct DFT Calculations
论文作者
论文摘要
Wiedemann-Franz定律中包含的Lorenz数（L）表示电子电荷载体的两个动力学参数的比率：电子对导热率（K_EL）和电导率（Sigma）的电子贡献，并且可以表示为lt = lt = k_el/sigma t温度。我们证明，洛伦兹的数量仅等于两个热力学量的比率：电子热容量（C_EL）和通过LT = C_EL/C_N（纯粹的热力学量）的电化学电容（C_N），因此可以单独根据材料状态的电子密度来计算。结果表明，我们对洛伦兹数量的热力学制定导致：i）在低温极限，ii）众所周知的sommerfeld值l = pi^2/3（k_b/e）^2，ii）drude值l = 3/2（k_b/e）^2（k_b/e）^2在高温限制的高温极限上，带有自由电子气体模型，以及III的高度值。还证明，可以直接使用高通量DFT计算直接计算对热电图的纯电子贡献，而无需诉诸于计算更昂贵的玻尔兹曼传输理论，以使电子导热率和电导率。
The Lorenz number (L) contained in the Wiedemann-Franz law represents the ratio of two kinetic parameters of electronic charge carriers: the electronic contribution to the thermal conductivity (K_el) and the electrical conductivity (sigma), , and can be expressed as LT=K_el/sigma where T is temperature. We demonstrate that the Lorenz number simply equals to the ratio of two thermodynamic quantities: the electronic heat capacity (c_el) and the electrochemical capacitance (c_N) through LT=c_el/c_N , a purely thermodynamic quantity, and thus it can be calculated solely based on the electron density of states of a material. It is shown that our thermodynamic formulation for the Lorenz number leads to: i) the well-known Sommerfeld value L=pi^2/3(k_B/e)^2 at the low temperature limit, ii) the Drude value L=3/2(k_B/e)^2 at the high temperature limit with the free electron gas model, and iii) possible higher values than the Sommerfeld limit for semiconductors. It is also demonstrated that the purely electronic contribution to the thermoelectric figure-of-merit can be directly computed using high-throughput DFT calculations without resorting to the computationally more expensive Boltzmann transport theory to the electronic thermal conductivity and electrical conductivity.
