论文标题
CAAL热电性能的第一原理研究$ _2 $ si $ _2 $ -Type Zintl阶段化合物
First principles study on the thermoelectric performance of CaAl$_2$Si$_2$-type Zintl phase compounds
论文作者
论文摘要
我们研究了CAAL $ _2 $ SI $ _2 $ -TYPE ZINTL相化合物$ ab_2x_2 $（$ a $ = mg，ca，ca，sr，ba，ba，ba，ba，ba = mg = mg = mg = mg = mg = mg = p，as，s，s，s，s，s，s，s，s，sb）使用首先放置boltzmann的常数，我们介绍了Valley Demeneracy $ n_ {TE} $的有效程度，以专注于热电属性与费米级围绕电子带结构的Multivalley角色之间的关系。我们还引入了一个数量$γ_{te} $，它考虑了$ n_ {te} $和山谷结构的各向异性，并且发现$γ_{TE} $使我们能够很好地了解功率因数物质依赖性的整体趋势。我们最终建议有希望的热电材料，例如BaMg$_2$P$_2$ for PF $\sim 20μ$W/cmK$^2$ and $ZT > 0.2$ at 300K and SrZn$_2$As$_2$ for PF $\sim 35μ$W/cmK$^2$ and $ZT > 0.35$ at 300K assuming a relaxation time of 10 fs and a lattice thermal conductivity value of 2 w/mk。
We investigate the thermoelectric properties of CaAl$_2$Si$_2$-type Zintl phase compounds $AB_2X_2$ ($A$ = Mg, Ca, Sr, Ba, $B$ = Mg, Zn, Cd, and $X$ = P, As, Sb) using first principles band calculations within the Boltzmann transport theory assuming the constant relaxation time approximation. We introduce the effective degree of valley degeneracy $n_{TE}$ to focus on the relationship between the thermoelectric properties and the multivalley character of the electronic band structure around the Fermi level. We also introduce a quantity $γ_{TE}$, which takes into account $n_{TE}$ and anisotropy of the valley structure, and it is found that $γ_{TE}$ enables us to well understand the overall trend of the material dependence of the power factor. We finally suggest promising thermoelectric materials, e.g. BaMg$_2$P$_2$ for PF $\sim 20μ$W/cmK$^2$ and $ZT > 0.2$ at 300K and SrZn$_2$As$_2$ for PF $\sim 35μ$W/cmK$^2$ and $ZT > 0.35$ at 300K assuming a relaxation time of 10 fs and a lattice thermal conductivity value of 2 W/mK.
