论文标题
与BI $ _2 $ te $ _3 $相比，Abax的非凡热电性能
Extraordinary thermoelectric performance of ABaX compared to Bi$_2$Te$_3$
论文作者
论文摘要
热电材料可以直接利用热量发电，因此被认为是环保能源。低温下的热电效率不切实际，只有几种散装材料（bi $ _2 $ te $ _3 $及其合金）。在这里，我预测两种新的热电材料Libasb和Nababi，使用第一原理方法在低中等温度下具有出色的运输特性。在费米水平附近的状态相对较低的状态密度，高度非促糖带和纳巴比的带隙近两倍，导致300K的各向异性功率因数几乎高两倍。另一方面，几乎相似的状态声子密度和纳巴比的非谐度导致晶格导热率几乎相同（但在libasb中却高得多）。这些效果使其成为一种优质的热电材料，对于N-和P型载体，在300 K时具有预测的跨平面（平面内）Zt〜2（〜1），甚至在350K时甚至更高（P型）更高（〜2.5）。另一方面，n和p型载体的Nababi的各向同性最大ZT分别为350K时约1.2和1.6。但是，由于Libasb相对较宽，并且具有较高的晶格导热率，因此Libasb不太适合低温TE应用。
Thermoelectric materials can generate electricity directly utilizing heat and thus, they are considered to be eco-friendly energy resources. The thermoelectric efficiency at low temperatures is impractically small, except only a few bulk materials (Bi$_2$Te$_3$ and its alloys). Here, I predict two new thermoelectric materials, LiBaSb and NaBaBi, with excellent transport properties at low-medium temperature by using the first-principles method. The relatively low density of states near Fermi level, highly non-parabolic bands, and almost two times wider bandgap of NaBaBi lead to almost two times higher anisotropic power factor at 300K than that of Bi2Te3. On the other side, almost similar phonon density of states and anharmonicity of NaBaBi cause almost identical lattice thermal conductivity (but it is much higher in LiBaSb). These effects make it a superior thermoelectric material, with a predicted cross-plane (in-plane) ZT ~2 (~1) at 300 K for both n- and p-type carriers, even higher (~2.5 for p-type) at 350K. On the other hand, the isotropic maximum ZT of NaBaBi is ~1.2 and 1.6 at 350K for n and p-type carriers, respectively. However, LiBaSb is less suitable for low-temperature TE applications, because of its relatively wider bandgap and high lattice thermal conductivity.
