中科大-Materials-Studio-培训教程9(包你学会!)请将这一系列全看完-一定有收获。.ppt

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1、TosetupaworkfunctioncalculationEitherimportastructureofthebulkmaterialfromapre-existingfileorconstructanewstructureusingthesketchingandcrystalbuildingtoolsintheMaterialsVisualizer.GeometryoptimizethebulkstructureusingCASTEP.CleavetherequiredcrystallographicsurfaceusingtheCle

2、aveSurfacedialogsothatthethicknessprovidesameaningfulrepresentationofthebulk.BuildavacuumslabusingtheBuildVacuumSlabCrystaldialog,youshouldensurethatthedistancebetweenthesurfaceandtheendofthevacuumisgreatenoughthattherecanbenopotentialinteractionsbetweenthesurfaceandthenextl

3、ayer.ChooseModules

4、CASTEP

5、Calculationfromthemenubar.SelecttheSetuptab.ChoosetheGeometryOptimizationtask.FixCartesianatomicpositionsofsomeatomsinthemiddleoftheslabusingtheEditConstraintsdialog,accessiblefromtheModifymenu.SelecteithertheLDAorGGAFunctionalfromthedropdownlist(se

6、ethetheorysectionformoreinformationonfunctionals).ClicktheRunbutton.FollowthestepsintheDisplayingtheaveragedpotentialchartforworkfunctioncalculationstopic.功函数计算1。输入一个软件自带的已知体结构，或用sketching和crystalbuilding工具建立一个新结构。GeometryoptimizethebulkstructureusingCASTEP.Cleavetherequired

7、crystallographicsurfaceusingtheCleaveSurfacedialogsothatthethicknessprovidesameaningfulrepresentationofthebulk.BuildavacuumslabusingtheBuildVacuumSlabCrystaldialog,youshouldensurethatthedistancebetweenthesurfaceandtheendofthevacuumisgreatenoughthattherecanbenopotentialintera

8、ctionsbetweenthesurfaceandthenextlayer.ChooseModules

9、CASTEP

10、Calculationfromthemenubar.SelecttheSetuptab.ChoosetheGeometryOptimizationtask.FixCartesianatomicpositionsofsomeatomsinthemiddleoftheslabusingtheEditConstraintsdialog,accessiblefromtheModifymenu.SelecteithertheLDAorG

11、GAFunctionalfromthedropdownlist(seethetheorysectionformoreinformationonfunctionals).ClicktheRunbutton.FollowthestepsintheDisplayingtheaveragedpotentialchartforworkfunctioncalculationstopic.功函数的计算一、热电子发射和功函数A：常数W：功函数(或脱出功)，将固体中的电子移至其表面、并处于自由状态所需的最低能量。V0EF0xVW金属真空热电子发射的电流密度为——

12、Richardson定律V0：真空能级（势阱的深度）W:2~6eV。此值与晶体方向有关，变化范围约1eV。二.功函数的计算模型构造如右图所示的2维无限