(上海交通大學(xué) 材料科學(xué)與工程學(xué)院
教育部高溫材料及測試開放實驗室， 上海 200030)
摘 要: 采用基于第一性原理的密度泛函理論全勢線性綴加平面波法計算CoSi的電子結(jié)構(gòu)及Si側(cè)Al置換摻雜的CoSi0.875Al0.125的電子結(jié)構(gòu)并分析兩者的電子結(jié)構(gòu)特征。 結(jié)果表明： CoSi為典型的半金屬化合物， 在費米面處價帶和導(dǎo)帶存在部分重疊且在費米面處電子能態(tài)密度值比較低， 因此其導(dǎo)電性能相對金屬的導(dǎo)電性能稍微差一些； 在理論計算的基礎(chǔ)上， 選擇制備CoSi和CoSi0.88Al0.12兩種單晶并測試了兩種單晶在300～1 000 K之間的塞貝克系數(shù)、 電阻率及300～480 K之間的熱導(dǎo)率。 隨著溫度的升高， CoSi的塞貝克系數(shù)變化不大， 而CoSi0.88-Al0.12的塞貝克系數(shù)呈降低的趨勢， 且存在一由正向負的轉(zhuǎn)變溫度， 隨著溫度的升高， CoSi和CoSi0.88Al0.12的電阻率都增大， CoSi的熱導(dǎo)率逐漸下降， 而CoSi0.88Al0.12的熱導(dǎo)率先下降然后上升。
關(guān)鍵字: 熱電材料; 電子結(jié)構(gòu); Al摻雜; 傳輸性能
（ Key Laboratory for High Temperature Materials and Testing, Ministry of Education, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China）
Abstract: By using the linearized augmented plane wave(LAPW) based on the density functional theory(DFT) of the first principles, the calculations of the electronic structures of CoSi and CoSi0.875Al0.125 were performed, the electronic structures of CoSi and CoSi0.875Al0.125 were analyzed and the CoSi and CoSi0.88Al0.12 single crystals were prepared. The temperature dependences of Seebeck coefficient and electrical resistivity at 300-1 000 K, and thermal conductivity at 300-480 K were characterized. The intrinsic relations between electronic structures of CoSi and CoSi0.875Al0.125 and transport performance of CoSi and CoSi0.88Al0.12 were discussed respectively.
Key words: thermoelectric materials; electronic structure; Al doping; transport performance
