北京工业大学学报
北京工業大學學報
북경공업대학학보
JOURNAL OF BEIJING POLYTECHNIC UNIVERSITY
2015年
1期
137-141,148
,共6页
刘富荣%韩欣欣%白楠%范振坤%朱赞
劉富榮%韓訢訢%白楠%範振坤%硃讚
류부영%한흔흔%백남%범진곤%주찬
相变%Ge2 Sb2 Te5%第一性原理%密度泛函
相變%Ge2 Sb2 Te5%第一性原理%密度汎函
상변%Ge2 Sb2 Te5%제일성원리%밀도범함
phase change%Ge2 Sb2 Te5%first-principle%density functional theory
基于密度泛函理论,采用CASTEP软件对Ge2 Sb2 Te5亚稳态晶体进行结构优化,并比较了局部密度泛函LDA CA-PZ和广义梯度近似GGA PBE两种不同电子交换关联函数对模型晶体结构、能带、态密度、分波态密度、布居数等相关性质的影响,获得Ge2 Sb2 Te5亚稳态晶体结构的性质。研究发现,电子交互关联函数采用局部密度泛函LDA CA-PZ时计算体系的总能量更低,具有更好的稳定性,但该优化使晶格常数缩小,而采用广义梯度近似GGA PBE方法对GST材料的晶胞结构进行模拟获得的结果与实验结果较为吻合。亚稳态Ge2 Sb2 Te5的能带没有带隙,呈现典型的金属性,而对材料性质影响最大的是Te原子。
基于密度汎函理論,採用CASTEP軟件對Ge2 Sb2 Te5亞穩態晶體進行結構優化,併比較瞭跼部密度汎函LDA CA-PZ和廣義梯度近似GGA PBE兩種不同電子交換關聯函數對模型晶體結構、能帶、態密度、分波態密度、佈居數等相關性質的影響,穫得Ge2 Sb2 Te5亞穩態晶體結構的性質。研究髮現,電子交互關聯函數採用跼部密度汎函LDA CA-PZ時計算體繫的總能量更低,具有更好的穩定性,但該優化使晶格常數縮小,而採用廣義梯度近似GGA PBE方法對GST材料的晶胞結構進行模擬穫得的結果與實驗結果較為吻閤。亞穩態Ge2 Sb2 Te5的能帶沒有帶隙,呈現典型的金屬性,而對材料性質影響最大的是Te原子。
기우밀도범함이론,채용CASTEP연건대Ge2 Sb2 Te5아은태정체진행결구우화,병비교료국부밀도범함LDA CA-PZ화엄의제도근사GGA PBE량충불동전자교환관련함수대모형정체결구、능대、태밀도、분파태밀도、포거수등상관성질적영향,획득Ge2 Sb2 Te5아은태정체결구적성질。연구발현,전자교호관련함수채용국부밀도범함LDA CA-PZ시계산체계적총능량경저,구유경호적은정성,단해우화사정격상수축소,이채용엄의제도근사GGA PBE방법대GST재료적정포결구진행모의획득적결과여실험결과교위문합。아은태Ge2 Sb2 Te5적능대몰유대극,정현전형적금속성,이대재료성질영향최대적시Te원자。
This paper optimized the structure of the metastable face centered cubic Ge2 Sb2 Te5 using the software CASTEP based on the density functional theory method. The numerical models were established by the local density function LDA CA-PZ and the generalized gradient approximation GGA PBE, and the effects of the two methods on the band, density of states, partial density of states, electron density, and other related properties were further compared and analyzed. The properties of the structure were obtained. Results showed that the structure of Ge2 Sb2 Te5 calculated by LDA CA-PZ had lower energy and better stability than that simulated by using GGA PBE. However, the lattice constant calculated by GGA PBE agreed well with experimental results while it was narrowing calculated by LDA CA-PZ. The metastable Ge2 Sb2 Te5 presented the typical metallic properties with no band gap while the greatest impact on the material properties was Te atoms.