CAJ | 학술논문

高温高压下,块体材料UO2存在许多缺陷,可能会沿不同的晶面解离,形成表面。本文采用基于第一性原理的LSDA+U方法,计算了铁磁和反铁磁状态下UO2(111)、(110)和(100)3种表面的结构、Bader电荷分布和磁矩等。结果显示2种磁性结构下3种表面中最稳定的是(111)面,最不稳定的是(100)面,原因是(100)表面U、O原子的Bader电荷布居数变小,并且表面与次表面U原子的磁矩变小,而表面O原子磁矩略微变大。最后,进一步计算了不同解离面的相对浓度在0到1600 K温度范围内的变化,计算结果表明,UO2(111)面的相对浓度是最高的。
고온고압하,괴체재료UO2존재허다결함,가능회연불동적정면해리,형성표면。본문채용기우제일성원리적LSDA+U방법,계산료철자화반철자상태하UO2(111)、(110)화(100)3충표면적결구、Bader전하분포화자구등。결과현시2충자성결구하3충표면중최은정적시(111)면,최불은정적시(100)면,원인시(100)표면U、O원자적Bader전하포거수변소,병차표면여차표면U원자적자구변소,이표면O원자자구략미변대。최후,진일보계산료불동해리면적상대농도재0도1600 K온도범위내적변화,계산결과표명,UO2(111)면적상대농도시최고적。
Bulk material UO2 may dissociate along different crystallographic planes and form surfaces under high temperature and high pressure. We apply LSDA+U approach based on first-principle to study three different sur-faces((111),(110) and(100)), and analyze their structures, Bader charge population and magnetic moments in AFM and FM states. The results show that the most stable surface is ( 111 ) , and opposed to it is ( 100 ) whose charge population of surface O atom largely reduced. The magnetic moments of surface and subsurface U atom of (100) surface are largely reduced while surface O atom slightly increased. At last, we calculate their relative con-centrations vary with temperature from 0 to 1 600 K, with a result that (111) surface dominate in the whole range of temperature.