本文選題：第一性原理計(jì)算 + 籠狀化合物　； 參考：《杭州電子科技大學(xué)》2015年碩士論文

【摘要】：本文主要的研究對(duì)象是Ba8T16P30(T=Cu,Au)、ATSb(A=Li,Cs,T=Zn,Cd)、In4X3(X=Se,Te)等幾種典型的具有低熱導(dǎo)率的熱電材料,利用基于密度泛函理論的第一性原理,采用兩種不同的交換勢(shì)函數(shù)研究了它們的電子結(jié)構(gòu)和熱電特性,并與實(shí)驗(yàn)結(jié)果做了對(duì)比。結(jié)合塞貝克系數(shù)和電阻率找出性能最優(yōu)時(shí)所對(duì)應(yīng)的載流子濃度,從而為實(shí)驗(yàn)研究?jī)?yōu)化其熱電性能提供參考和指導(dǎo)。研究所取得的主要成果總結(jié)如下:(1)首次利用第一性原理研究了籠狀化合物Ba8T16P30(T=Cu,Au)的電子結(jié)構(gòu)和熱電特性。這兩種化合物的塞貝克系數(shù)均為正的,表明它們均是P型半導(dǎo)體。兩種化合物的輸運(yùn)性質(zhì)計(jì)算實(shí)驗(yàn)結(jié)果與現(xiàn)有文獻(xiàn)報(bào)道結(jié)果定性一致。(2)對(duì)ATSb(A=Li,Cs,T=Zn,Cd)的晶體結(jié)構(gòu)進(jìn)行優(yōu)化,發(fā)現(xiàn)化合物L(fēng)i CdSb和CsZnSb比Li ZnSb的能量更低,首次從理論上預(yù)測(cè)了這兩種新化合物的存在。計(jì)算結(jié)果表明,LiCdSb為半導(dǎo)體,而CsZnSb呈現(xiàn)出金屬性質(zhì)。(3)采用修正的Becke-Jonson(mBJ)交換勢(shì),計(jì)算了In4Se3和In4Te3電子結(jié)構(gòu),繼而計(jì)算了它們的塞貝克系數(shù)隨溫度和載流子濃度的變化。很好地再現(xiàn)了不同文獻(xiàn)所給出的實(shí)驗(yàn)結(jié)果。揭示了不同實(shí)驗(yàn)結(jié)果存在顯著差異的原因主要來自不同制備工藝造成的材料的載流子濃度的差異。
[Abstract]:In this paper, several typical thermoelectric materials with low thermal conductivity, such as Ba8T16P30TCU, ATSbCsTZN, Tznznzcdznzncdzhuanzhuang (In4X3), are studied by using the first principle based on density functional theory (DFT) and using two different exchange potential functions to study their electronic structure and thermoelectric properties, and the results are as follows: (1) in this paper, the electronic structure and thermoelectric properties of these materials are studied by using the first principle based on density functional theory (DFT), and two different exchange potential functions are used. The results are compared with the experimental results. The carrier concentration corresponding to the optimum performance can be found by combining Seebeck coefficient and resistivity, thus providing a reference and guidance for the experimental study on the optimization of its thermoelectric performance. The main results obtained are summarized as follows: (1) the electronic structure and thermoelectric properties of cage compound Ba8T16P30 (TCU) are studied by first principle. The Seebeck coefficients of these two compounds are positive, indicating that they are P-type semiconductors. The calculated results of transport properties of the two compounds are qualitatively consistent with the reported results in the literature. (2) the crystal structure of ATSbSb LiCsTsTznznzncdcdd) is optimized. It is found that the energy of the compounds Li CdSb and CsZnSb are lower than that of Li ZnSb, and the energy of these compounds is lower than that of LiZnSb. The existence of these two new compounds is predicted theoretically for the first time. The calculated results show that LiCdSb is a semiconductor, while CsZnSb exhibits metal properties. The modified Becke-JonsonsonmBJ) exchange potential is used to calculate the electronic structures of In4Se3 and In4Te3, and the variation of their Sebek coefficients with temperature and carrier concentration is calculated. The experimental results given in different literatures are well reproduced. It is revealed that the main reasons for the significant differences in experimental results are due to the differences in carrier concentration of materials due to different preparation processes.
【學(xué)位授予單位】：杭州電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB34

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本文編號(hào)：2031477