阻挫三角反铁磁AgCrO2螺旋自旋序的第一性原理研究

基于密度泛函理论的广义梯度近似(GGA)和投影缀加波(PAW)方法,分别从共线和非共线磁性结构出发,研究了自旋阻挫三角反铁磁AgCrO₂的基态、磁性以及电子结构,从理论计算的角度给出了基态磁性结构.计算结果表明:AgCrO₂具有120°螺旋自旋序反铁磁基态,其自旋螺旋面平行于(110)面或(11^-0)面;由于Cr离子间的自旋几何阻挫,导致沿晶体的a,b和a+b方向上均形成了螺旋自旋转动角为120°的 关键词： 第一性原理 交换相互作用 阻挫 反铁磁

First-principles studies of helical-spin order in frustrated triangular antiferromagnet AgCrO2

Based on the collinear and non-collinear magnetic structures, the ground state, magnetism and electronic structure of the frustrated triangular antiferromagnet AgCrO₂ have been investigated using the density functional theory (DFT) within the generalized gradient approximation (GGA) with the projected augmented wave (PAW) method. Detailed magnetic structure has been elucidated vividly from the theoretical view. The calculations show that AgCrO₂ magnetic ground state has 120° helical-spin order with its spiral plane parallel to the (110)or (11 0) plane. Due to the strong intra- and interlayer geometric spin frustration, parallel helical-spin chains arise along the a,b or a+b direction with the screw-rotation angle 120°. From the non-collinear electronic structure calculation, it is found that due to the spin frustration Cr-3d orbital states near the Fermi level become more localized, indicating an enhanced interaction between Cr-Cr. Nevertheless, the spin-orbit coupling has weak influence on the electron structure.