Jeffrey Snyder：通過費米表面複雜性因數，高通量搜尋新型熱電材料

海歸學者發起的公益學術平臺

分享資訊，整合資源

交流學術，偶爾風月

電子在固體內的環境相當複雜，但其在原子晶格內仍可視為自由移動。不過在類比電子的運動和材料的性能時，需要用有效品質代替其真實品質作為參數，以考慮電子受固體內環境的影響。有效品質是電子能帶結構方便的描述參量，但其定義有多種方式，每種可描述電子傳輸的某方面特徵，與被類比的材料特定性質相關。美國西北大學G. Jeffrey Snyder教授等基於第一性原理開展了玻爾茲曼輸運計算，

類比不同的電子輸運特性。他們從塞貝克係數提取態密度有效品質、從電導率提取慣性品質來表徵能帶結構，發現可用這兩種有效品質的比值確定材料費米表面複雜性因數Nv * K *。在簡單體系中這一因數取決於費米表面袋的數量（N v *）及體系的各向異性K *，兩者都有利於提高材料熱電性能。如經典的PbTe就具有較高的Nv * K *。因此，費米表面複雜性因數可用于高通量搜索高性能的新型熱電材料。

該文近期發表於npj Computational Materials 3: 7 (2017)，標題與摘要如下，論文PDF文末點擊閱讀原文可以獲取。

Effective mass and Fermi surfacecomplexity factor from ab initio band structure calculations

Zachary M Gibbs,Francesco Ricci, Guodong Li, Hong Zhu, Kristin Persson, GerbrandCeder, GeoffroyHautier, AnubhavJain & G.Jeffrey Snyder

The effective mass is a convenientdescriptor of the electronic band structure used to characterize the density ofstates and electron transport based on a free electron model. While effectivemass is an excellent first-order descriptor in real systems, the exact valuecan have several definitions, each of which describe a different aspect ofelectron transport. Here we use Boltzmann transport calculations applied to abinitio band structures to extract a density-of-states effective mass from theSeebeck Coefficient and an inertial mass from the electrical conductivity tocharacterize the band structure irrespective of the exact scattering mechanism.We identify a Fermi Surface ComplexityFactor: Nv * K * from the ratio of these two masses,which in simple cases depends on the number of Fermi surfacepockets ( N v * ) and their anisotropy K*,both of which are beneficial to high thermoelectric performance as exemplifiedby the high values found in PbTe. The Fermi Surface Complexity factor can beused in high-throughput search of promising thermoelectric materials.

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