钆、氟掺杂二氧化钒的晶体结构演变行为与相变机理
Crystal structure evolution behavior and phase transformation mechanism of Gd and F doped vanadium dioxide
曲道宇 1栾敬德 1刘文刚 2可欣 1烟征 1陶佳璐3
作者信息
- 1. 沈阳航空航天大学 能源与环境学院,沈阳 110136
- 2. 东北大学 资源与土木工程学院,沈阳 110167
- 3. 辽宁省计量科学研究院,沈阳 110006
- 折叠
摘要
二氧化钒(VO2)是一种热致相变材料,其过高的相变温度制约了其潜在应用.元素掺杂能够使VO2的能带结构、态密度、键长和晶胞体积等晶格参数改变,引起其相变行为的变化.借助Materials Studio软件,基于第一性原理和分子轨道理论研究了钆、氟掺杂二氧化钒的晶体结构演变行为与相变机理.结果表明,无论F掺杂于VO2(M型)中间O的位置还是两侧O位置,都会引起O—O键收缩,V—V键增长,β角增大,体系亥姆霍自由能增加,带隙相对减小,F侧位掺杂效果最好,随着V4+—V4+同极结合的减少,在1 at%F掺杂时相变温度达到最低;当Gd以0-1.8 at%掺杂于VO2(M)中V位置时,O—O键和V—V键发生收缩,β角减小,亥姆霍自能增加,带隙减小,Gd 4f态与tⅡ轨道重合,使相变能垒变低,相变温度显著降低.钆、氟两种元素掺杂VO2相变机理更符合Peierls-Mott协同相变.
Abstract
Vanadium dioxide(VO2)is a thermally induced phase change material,the high phase change tem-perature restricts its potential application.Elemental doping can cause the changes in the properties of VO2 such as band structure,state density,bond length and cell volume,resulting in the change of phase transition behav-ior.Using Materials Studio software,based on first principles and molecular orbital theory,the crystal structure evolution and phase transformation mechanism of Gd and F doped VO2 were studied,it was found that no matter F doping in the middle O position of VO2(M)or O position on both sides,the doping will cause O—O bond to contract,V—V bond to growth,β Angle to increase,system Helmholm self-energy to increase,band gap to be relative reduction,F on both sides of the doping effect is the best.With the decrease of V4+—V4+ unipolar bonding,the phase transition temperature reaches the lowest at 1at％ F doping.When Gd is doped in V position in VO2(M)at 0-1.8at％,O—O bond and V—V bond shrink,β Angle decreases,Helmholm self-energy in-creases,band gap decreases,and Gd 4f state coincides with tⅡ orbital,so that the phase transition energy barrier becomes lower and the phase transition temperature decreases significantly.The phase transition mechanism of gadolinium and fluorine doped VO2 is more consistent with Peierls-Mott synergistic phase transition.
关键词
二氧化钒/元素掺杂/晶体结构演变/第一性原理/密度泛函理论/相变机理Key words
Vanadium dioxide/Element doping/Crystal structure evolution/First principles/Density function-al theory/Phase transformation mechanism引用本文复制引用
基金项目
辽宁省兴辽人才计划(XLYC1807045)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据