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利用分子动力学中的静态结构计算方法对Pd,Ag及Cu原子在面心立方铜的台阶表面扩散过程中的Ehrlich-Schwoebel(ES)势垒进行了模拟计算,研究了各种台阶表面情况下增原子扩散过程中的ES势垒;讨论了与衬底互溶的金属和与衬底不互溶的金属增原子扩散的ES势垒的异同,并将模拟结果与同质情况的研究结果进行了对比.结果表明:1)在同质和异质扩散过程中ES势垒随着台阶高度的变化关系是相似的,即随着台阶高度的增加,ES势垒逐渐增加;当台阶高度达到某一高度时ES势垒将趋于定值.2)在跳跃机理下,与Cu互溶的金属(Pd)在Cu表面台阶上扩散的ES势垒最大,其次是Cu,最小的是与Cu不互溶的金属(Ag);而在交换机理下,与Cu不互溶的金属(Ag)在Cu表面台阶上扩散的ES势垒最大,其次是Cu,最小的是与Cu互溶的金属(Pd).3)对大多数台阶的情况,交换机理支配着原子在台阶边缘的扩散行为;且表面台阶高度对交换扩散过程影响较大.
The Ehrlich-Schwoebel (ES) barrier in the diffusion process of Pd, Ag and Cu atoms on the step surface of face-centered cubic copper has been simulated by the static structure calculation method in molecular dynamics. The effects of various step surfaces The ES barriers in the process of atom diffusion are discussed. The similarities and differences of the ES barriers between the diffusion of metals and the miscible metals with the substrate are discussed, and the simulation results are compared with the results of homogeneous research The results show that: 1) The relationship between ES barrier and step height is similar in the process of homogenous and heterogeneous diffusion, that is, ES barrier gradually increases with the increase of step height; when step height reaches a certain height The ES barrier tends to be constant.2) Under the leaping mechanism, the barrier metal (Pd) that diffuses with Cu on Cu surface has the largest ES barrier, followed by Cu and the smallest metal that is immiscible with Cu (Ag). However, under the exchange mechanism, the ES barrier of the Cu-immiscible metal (Ag) diffused on the surface of the Cu surface was the largest, followed by Cu and the smallest was the metal (Pd) miscible with Cu. In the case of most steps, the exchange mechanism dominates the diffusion of atoms around the steps; and the surface Step height greater impact on exchange diffusion process.