摘要
基于密度泛函的第一性原理计算了各向同性应力下铌酸钾钠的电子结构和光学性质。结果表明:在各向同性应力作用下铌酸钾钠表现出正交相结构。当压应力从0 GPa增大到25 GPa时,晶格常数a、b、c都相应减小。拉应力从0~-25 GPa时,晶格常数a从3.96Å增大到6.14Å,b、c都经历先增大后减小的趋势。在0 GPa到25 GPa压应力下,铌酸钾钠带隙宽度从2.38 eV逐渐减小至2.06 eV。在0~-25 GPa拉应力作用下带隙宽度表现出跳跃性的趋势。施加拉应力时0 eV附近态密度有所增加,价带顶和导带底的电子轨道向费米能级靠近。随着压应力的增加,介电函数实部最大峰值略有减小,且出现了最大峰值向高能量方向移动的现象。拉应力作用下铌酸钾钠的静态介电常数从4.50减小到2.24。
Based on the first-principles density functional theory calculations,the electronic structure and optical properties of potassium sodium niobate under isotropic stress were investigated.The results indicated that potassium sodium niobate maintained an orthorhombic phase structure under isotropic stress.As compressive stress increased from 0 GPa to 25 GPa,the lattice constants a,b and c decreased accordingly.Under tensile stress from 0 GPa to−25 GPa,lattice constant a increases from 3.957Åto 6.139Å,while b and c exhibited an initial increase followed by a decrease.Within the compressive stress range of 0 GPa to 25 GPa,the band gap of potassium sodium niobate gradually decreased from 2.383 eV to 2.064 eV.Under tensile stress from 0 GPa to−25 GPa,the band gap showed an abrupt,non-monotonic variation.The application of tensile stress increased the density of states near 0 eV,with the electron orbitals at the valence band maximum and conduction band minimum shifting closer to the Fermi level.With increasing compressive stress,the maximum peak of the real part of the dielectric function slightly decreased and shifts toward higher energies.Under tensile stress,the static dielectric constant of potassium sodium niobate decreased from 4.50 to 2.24.
作者
杨飘
杨小驰
何雄飞
杨秀凡
YANG Piao;YANG Xiaochi;HE Xiongfei;YANG Xiufan(Electronic Information Engineering Institute,Anshun University,Guizhou Anshun 561000,China)
出处
《广州化工》
2026年第2期46-49,共4页
GuangZhou Chemical Industry
基金
安顺学院大学生SRT项目(asxysrt202220)
省级大学生创新创业训练计划项目(S202210667122)。
关键词
第一性原理
应力作用
铌酸钾钠
性能
first principles
stress effects
potassium sodium niobate
properties
