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作者江南清（2019）在《热电材料SrSi2掺杂的第一性原理研究》一文中研究指出：从十九世纪Seebeck效应和Peltier效应被发现起,热电材料就进入了人们的视野,吸引着无数科研人员的探索。到目前为止已经发现了很多类型的热电材料,它们有着各自的优点,可以应用于不同的场合。然而所有的热电材料都有热电转换效率的问题,提高热电优值是我们科研人员努力的方向。环境友好硅化物热电材料SrSi2就由于室温下热电优值不高,使得应用受到限制。许多文献中指出,掺杂可以改善材料的热电性能,基于这一理念,我们对SrSi2进行了掺杂研究。本文是基于密度泛函理论,应用第一性原理研究Sr1-xMxSi2（M=Ca和Ba）（x=0,0.25,0.5,0.75和1）的结构性质,电子性质和光学性质。首先,我们用Ca对SrSi2进行掺杂,计算了纯SrSi2和Sr1-xCaxSi2（x=0.25,0.5,0.75和1）的晶格常数、键长、Mulliken布居、能带、态密度和一些光学常数（包括介电函数、吸收系数、反射率和损耗函数）。我们发现随着掺杂浓度的增大,Sr1-xCaxSi2的晶格常数减小,晶体结构发生明显的压缩,而造成这种现象的原因是掺杂Ca原子使得SrSi2基中产生了一个正的化学压力,并且当掺杂浓度为0.5时,Sr0.5Ca0.5Si2会有一个相的转变,由立方相向四方相转变。我们计算了立方相和四方相的总能,发现四方相的总能低于立方相,四方结构更稳定。另外,带结构的计算表明,SrSi2是一个拥有间接带隙的半导体,随着掺杂浓度的增大,Sr1-xCaxSi2的带隙减小,当掺杂浓度大于或者等于0.5时,带隙消失,也就是说Ca的替代能够使得SrSi2由半导体向金属转变。电阻率与能隙有关,带隙值减小,那么电阻率相应减小,热电优值得到提升。我们计算了纯SrSi2和掺杂Ca原子后的静态介电常数,计算结果表明掺杂后静态介电常数会有一个较大的提升,这说明Sr1-xCaxSi2是一个良好的介电材料。其次,我们计算了Ba原子对SrSi2掺杂后的晶格常数、键长、Mulliken布居、能带、态密度和光学常数。Sr1-xBaxSi2的晶格常数随掺杂浓度的增大而增大,系统中产生一个负的化学压力,晶体结构发生膨胀。这个结果与掺杂Ca的情况是完全相反的,因为Ca原子的半径小于Sr原子,而Ba原子的半径大于Sr原子。与掺杂Ca原子的情况相类似,当掺杂浓度为0.5时,Sr0.5Ba0.5Si2会从立方相向四方相转变,并且四方相的总能更低,更加稳定。我们计算了Sr1-xBaxSi2的能带结构,发现Sr1-xBaxSi2的能隙值比纯SrSi2更大,意味着掺杂Ba原子以后,SrSi2的半导体性质得到了增强,这一结果也对应高温电阻率的降低,因此热电优值增大。Ba原子的掺杂也使得SrSi2的光学性质发生了很大的变化,静态介电常数随Ba原子浓度的增加呈先增大后减小的趋势。掺杂可以改变材料费米能级附近的电子能带结构,从而有机会改善材料的热电性能,因此研究热电材料的结构性质和电子性质可以为寻找性能优良的热电材料提供理论指导。
Abstract
cong shi jiu shi ji Seebeckxiao ying he Peltierxiao ying bei fa xian qi ,re dian cai liao jiu jin ru le ren men de shi ye ,xi yin zhao mo shu ke yan ren yuan de tan suo 。dao mu qian wei zhi yi jing fa xian le hen duo lei xing de re dian cai liao ,ta men you zhao ge zi de you dian ,ke yi ying yong yu bu tong de chang ge 。ran er suo you de re dian cai liao dou you re dian zhuai huan xiao lv de wen ti ,di gao re dian you zhi shi wo men ke yan ren yuan nu li de fang xiang 。huan jing you hao gui hua wu re dian cai liao SrSi2jiu you yu shi wen xia re dian you zhi bu gao ,shi de ying yong shou dao xian zhi 。hu duo wen suo zhong zhi chu ,can za ke yi gai shan cai liao de re dian xing neng ,ji yu zhe yi li nian ,wo men dui SrSi2jin hang le can za yan jiu 。ben wen shi ji yu mi du fan han li lun ,ying yong di yi xing yuan li yan jiu Sr1-xMxSi2（M=Cahe Ba）（x=0,0.25,0.5,0.75he 1）de jie gou xing zhi ,dian zi xing zhi he guang xue xing zhi 。shou xian ,wo men yong Cadui SrSi2jin hang can za ,ji suan le chun SrSi2he Sr1-xCaxSi2（x=0.25,0.5,0.75he 1）de jing ge chang shu 、jian chang 、Mullikenbu ju 、neng dai 、tai mi du he yi xie guang xue chang shu （bao gua jie dian han shu 、xi shou ji shu 、fan she lv he sun hao han shu ）。wo men fa xian sui zhao can za nong du de zeng da ,Sr1-xCaxSi2de jing ge chang shu jian xiao ,jing ti jie gou fa sheng ming xian de ya su ,er zao cheng zhe chong xian xiang de yuan yin shi can za Cayuan zi shi de SrSi2ji zhong chan sheng le yi ge zheng de hua xue ya li ,bing ju dang can za nong du wei 0.5shi ,Sr0.5Ca0.5Si2hui you yi ge xiang de zhuai bian ,you li fang xiang xiang si fang xiang zhuai bian 。wo men ji suan le li fang xiang he si fang xiang de zong neng ,fa xian si fang xiang de zong neng di yu li fang xiang ,si fang jie gou geng wen ding 。ling wai ,dai jie gou de ji suan biao ming ,SrSi2shi yi ge yong you jian jie dai xi de ban dao ti ,sui zhao can za nong du de zeng da ,Sr1-xCaxSi2de dai xi jian xiao ,dang can za nong du da yu huo zhe deng yu 0.5shi ,dai xi xiao shi ,ye jiu shi shui Cade ti dai neng gou shi de SrSi2you ban dao ti xiang jin shu zhuai bian 。dian zu lv yu neng xi you guan ,dai xi zhi jian xiao ,na me dian zu lv xiang ying jian xiao ,re dian you zhi de dao di sheng 。wo men ji suan le chun SrSi2he can za Cayuan zi hou de jing tai jie dian chang shu ,ji suan jie guo biao ming can za hou jing tai jie dian chang shu hui you yi ge jiao da de di sheng ,zhe shui ming Sr1-xCaxSi2shi yi ge liang hao de jie dian cai liao 。ji ci ,wo men ji suan le Bayuan zi dui SrSi2can za hou de jing ge chang shu 、jian chang 、Mullikenbu ju 、neng dai 、tai mi du he guang xue chang shu 。Sr1-xBaxSi2de jing ge chang shu sui can za nong du de zeng da er zeng da ,ji tong zhong chan sheng yi ge fu de hua xue ya li ,jing ti jie gou fa sheng peng zhang 。zhe ge jie guo yu can za Cade qing kuang shi wan quan xiang fan de ,yin wei Cayuan zi de ban jing xiao yu Sryuan zi ,er Bayuan zi de ban jing da yu Sryuan zi 。yu can za Cayuan zi de qing kuang xiang lei shi ,dang can za nong du wei 0.5shi ,Sr0.5Ba0.5Si2hui cong li fang xiang xiang si fang xiang zhuai bian ,bing ju si fang xiang de zong neng geng di ,geng jia wen ding 。wo men ji suan le Sr1-xBaxSi2de neng dai jie gou ,fa xian Sr1-xBaxSi2de neng xi zhi bi chun SrSi2geng da ,yi wei zhao can za Bayuan zi yi hou ,SrSi2de ban dao ti xing zhi de dao le zeng jiang ,zhe yi jie guo ye dui ying gao wen dian zu lv de jiang di ,yin ci re dian you zhi zeng da 。Bayuan zi de can za ye shi de SrSi2de guang xue xing zhi fa sheng le hen da de bian hua ,jing tai jie dian chang shu sui Bayuan zi nong du de zeng jia cheng xian zeng da hou jian xiao de qu shi 。can za ke yi gai bian cai liao fei mi neng ji fu jin de dian zi neng dai jie gou ,cong er you ji hui gai shan cai liao de re dian xing neng ,yin ci yan jiu re dian cai liao de jie gou xing zhi he dian zi xing zhi ke yi wei xun zhao xing neng you liang de re dian cai liao di gong li lun zhi dao 。
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论文作者分别是来自电子科技大学的江南清，发表于刊物电子科技大学2019-07-17论文，是一篇关于热电材料论文,第一性原理论文,掺杂论文,电子结构论文,光学性质论文,电子科技大学2019-07-17论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自电子科技大学2019-07-17论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：热电材料论文; 第一性原理论文; 掺杂论文; 电子结构论文; 光学性质论文; 电子科技大学2019-07-17论文;