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arXiv 2108.09969cond-mat.mtrl-sci
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LaNiO3化合物在300-620 K温度范围内塞贝克系数的研究

Understanding the Seebeck coefficient of LaNiO3 compound in the temperature range 300-620 K

Arzena Khatun, Shamim Sk, Sudhir K. Pandey

摘要:

近几十年来,过渡金属氧化物热电材料一直是热电界的研究热点。在本工作中,我们已经合成了LaNiO $_{3}$通过一个简单的溶液燃烧过程。为了分析晶体结构和结构参数,我们使用Rietveld精修方法,其中采用FullProf软件。室温X射线衍射表明具有空间群$R \, \overline{3} \, c$(No.167)的三角结构。晶格参数的精确值为a = b = 5.4615 Ω\,$\&$ c = 13.1777 Ω。利用实验和计算工具研究了该化合物的Seebeck系数(S)随温度的变化。S的测量在温度范围$300-620$ K内进行。在整个温度范围内S的测量值具有负号,其指示化合物的\textit{n}型特征。在300 K时S值为$\sim$ $-$ 8 $μ$ V/K,在620 K时S值为$\sim$ $-$ 12 $μ$ V/K。由于LaNiO $_{3}$具有很强的相关性,采用DFT+ \textit{U}方法进行了电子结构计算.计算预测了化合物的金属基态。用BoltzTraP程序计算了S随温度的变化,并与实验结果进行了比较。在自旋极化DFT + \textit{U}(= 1 eV)计算中,采用自相互作用修正作为双计数修正时,观测到S的实验值与计算值之间的最佳匹配.根据计算结果,还计算了该化合物的\textit{p}型和\textit{n}型掺杂的最大功率因子。

英文摘要:

Transition metal oxides have been attracted much attention in thermoelectric community from the last few decades. In the present work, we have synthesized LaNiO$_{3}$ by a simple solution combustion process. To analyze the crystal structure and structural parameters we have used Rietveld refinement method wherein FullProf software is employed. The room temperature x-ray diffraction indicates the trigonal structure with space group $R \, \overline{3} \, c$ (No. 167). The refined values of lattice parameters are a = b = 5.4615 Å\, $\&$ c = 13.1777 Å. Temperature dependent Seebeck coefficient (S) of this compound has been investigated by using experimental and computational tools. The measurement of S is conducted in the temperature range $300-620$ K. The measured values of S in the entire temperature range have negative sign that indicates \textit{n}-type character of the compound. The value of S is found to be $\sim$ $-$8 $μ$V/K at 300 K and at 620 K this value is $\sim$ $-$12 $μ$V/K. The electronic structure calculation is carried out using DFT+\textit{U} method due to having strong correlation in LaNiO$_{3}$. The calculation predicts the metallic ground state of the compound. Temperature dependent S is calculated using BoltzTraP package and compared with experiment. The best matching between experimental and calculated values of S is observed when self-interaction correction is employed as double counting correction in spin-polarized DFT + \textit{U} (= 1 eV) calculation. Based on the computational results maximum power factors are also calculated for \textit{p}-type and \textit{n}-type doping of this compound.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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