CrXN (x=1,2)的电子特性和相稳定性的第一性原理研究.doc

文档介绍：
CrxN (x=1,2)的电子特性和相稳定性的第一
性原理研究#
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(亚稳材料制备技术与科学国家重点实验室,燕山大学,河北省秦皇岛市 066004)
摘要:采用第一性原理方法计算了 CrxN (x=1,2)的结构、电子性质和磁性,分析了 Cr2N (x=1,2)在高压下
(低于 40 GPa)的相稳定性。理论分析表明:Cr2N 的稳定性高于 c-CrN(立方结构)和 o-CrN(正交结构),
证实了高氮钢中 Cr2N 先于 CrN 析出,预测了在 25GPa 左右,c-CrN 向 o-CrN 发生转变的相转变形式。c-CrN
和 o-CrN 的磁矩随着压强的增大而不断减小。低于 25GPa 时,o-CrN 的磁矩高于 c-CrN 的磁矩,而在高于
25GPa 时,c-CrN 的磁矩高于 o-CrN 的磁矩。在压强为 0~ 40GPa 时,Cr2N 表现为顺磁性。
关键词:电子性质;高压;氮化物材料;晶体结构
中图分类号:
The electronic properties and phase stability of CrxN (x=1,2):
the first-principles investigations
DONG Fan, LV Zhiqing, FU Wantang
(State Key Laboratory of Metastable Material Science and Technology,Yanshan
University,Qinghuangdao 066004,China)
Abstract: The structural, electronic and ic properties of CrxN (x=1,2) have been presented
by the use of the first-principles technique. The phase stability of CrxN (x=1,2) were also analyzed
under high pressure (up to 40 GPa). The theoretical analyses show that the energetic stability of
Cr2N is higher than c-CrN (cubic structure) and o-CrN (orthorhombic structure). This confirms
that Cr2N prior to CrN precipitates in high nitrogen steels. The phase transition form c-CrN to
o-CrN is predicted at about 25 GPa. The ic moments of c-CrN and o-CrN decrease with the
increase of the pressure. Under less than 25 Gpa, the ic moment of o-CrN is higher than
c-CrN, but the mo