Magnetic behavior of Fe(Se,Te) systems: First-principles calculations

作者：Shi Hongliang; Huang Zhong Bing^*; Tse John S; Lin Hai Qing

来源：Journal of Applied Physics, 2011, 110(4): 043917.

DOI：10.1063/1.3624759

The magnetic behaviors in Fe(Se,Te) systems have been investigated systematically using density functional calculations. At the experimental lattice parameters, the ground state is found to be in the double stripe magnetic phase for FeTe but in the single stripe magnetic phase for FeSe and FeSe(0.5)Te(0.5), and there is no preference in the different easy axes of magnetization. Substitution of Se by Te enlarges the size of the Fermi surface in FeSe(0.5)Te(0.5), resulting in a stronger nesting effect and thus enhancing the superconductivity. It is found that the double stripe order in FeTe(1-x)Se(x) changes to the single stripe order when x > 0.18. Spiral calculations on FeSe(0.5)Te(0.5) show that the lowest energy is at the commensurate point (Q) over right arrow = (0.5,0.5), accompanied by additional local minima at two incommensurate points near (Q) over right arrow = (0.5,0.5). This observation is consistent with the experimentally observed positions of low energy magnetic excitations. Geometry optimization calculations show that the tetragonal cell relaxes to orthorhombic and monoclinic cells for FeSe and FeTe, respectively, but remains unchanged for FeSe(0.5)Te(0.5).

• 出版日期2011-8-15
• 单位北京计算科学研究中心; 湖北大学