论文标题
探测有效的n型灯笼掺杂剂，以$ _3 $ _3 $ SB $ _2 $热电学
Probing efficient n-type lanthanide dopants for Mg$_3$Sb$_2$ thermoelectrics
论文作者
论文摘要
最近发现N型毫克$ _3 $ SB $ _2 $热电学的发现引发了密集的研究活动，以寻找该材料的潜在N型掺杂剂。使用第一原理缺陷计算，在这里，我们对Mg $ _3 $ _3 $ sb $ _2 $的潜在有效N型灯笼掺杂剂进行了系统的计算筛选。除了LA，CE，PR和TM外，我们还发现，在900 K的生长温度下，可以通过使用ND，GD，HO和LU在MG网站上掺杂，在900 K的生长温度下，高电子浓度（$ \ geq $ 10 $^{20} $ cm $^{ - 3} $通常可以实现，通常比其他Lanthanide dopants和anthanide dopants andantantant和lu更有效。在实验上，我们确认ND和TM为有效的n型掺杂剂，以$ _3 $ _3 $ SB $ _2 $，因为与ND和TM一起掺杂显示了优异的ZT $ \ GEQ $ 1.3的优越的热电学图，其电子浓度高于TE掺杂。通过使用ND（TM）和TE进行编码，可以同时提高功率因数改善和导热率降低。结果，我们在775 k中获得约1.65和1.75的高ZT值，n型毫克$ _ {3.5} $ nd $ _ {0.04} $ _ {0.04} $ sb $ _ {1.97} mg $ _ {3.5} $ tm $ _ {0.03} $ sb $ _ {1.97} $ te $ _ {0.03} $，这是N型MG $ _3 $ _2 $ _2 $的最高价值之一，而无需与mg $ $ _3 $ _3 $ _3 $ _2 $ _2 $ _2 $ _2 $ _2 $。这项工作阐明了探索有希望的N型掺杂剂，以设计毫克$ _3 $ sb $ _2 $热电学。
The recent discovery of n-type Mg$_3$Sb$_2$ thermoelectric has ignited intensive research activities on searching for potential n-type dopants for this material. Using first-principles defect calculations, here we conduct a systematic computational screening of potential efficient n-type lanthanide dopants for Mg$_3$Sb$_2$. In addition to La, Ce, Pr, and Tm, we find that high electron concentration ($\geq$ 10$^{20}$ cm$^{-3}$ at the growth temperature of 900 K) can be achieved by doping on the Mg sites with Nd, Gd, Ho, and Lu, which are generally more efficient than other lanthanide dopants and the anion-site dopant Te. Experimentally, we confirm Nd and Tm as effective n-type dopants for Mg$_3$Sb$_2$ since doping with Nd and Tm shows superior thermoelectric figure of merit zT $\geq$ 1.3 with higher electron concentration than doping with Te. Through codoping with Nd (Tm) and Te, simultaneous power factor improvement and thermal conductivity reduction are achieved. As a result, we obtain high zT values of about 1.65 and 1.75 at 775 K in n-type Mg$_{3.5}$Nd$_{0.04}$Sb$_{1.97}$Te$_{0.03}$ and Mg$_{3.5}$Tm$_{0.03}$Sb$_{1.97}$Te$_{0.03}$, respectively, which are among the highest values for n-type Mg$_3$Sb$_2$ without alloying with Mg$_3$Bi$_2$. This work sheds light on exploring promising n-type dopants for the design of Mg$_3$Sb$_2$ thermoelectrics.
