Sasabe Norimasa, Kimata Motoi, Nakamura Tetsuya
Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan.
Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577, Japan.
Phys Rev Lett. 2021 Apr 16;126(15):157402. doi: 10.1103/PhysRevLett.126.157402.
X-ray magnetic circular dichroism (XMCD) is generally not observed for antiferromagnetic (AFM) states because XMCD signals from the antiparallelly coupled spins cancel each other. In this Letter, we theoretically show the presence of an XMCD signal from compensated two-dimensional triangle AFM structures on a Kagome lattice. The calculation reveals the complete correspondence between the XMCD spectra and the sign of the spin chirality: the XMCD signal only appears when the spin chirality is negative. This XMCD signal originates from the different absorption coefficients of the three sublattices reflecting different charge density anisotropies and directions of spin and orbital magnetic moments.
对于反铁磁（AFM）态，通常观察不到X射线磁圆二色性（XMCD），因为来自反平行耦合自旋的XMCD信号会相互抵消。在本信函中，我们从理论上证明了在Kagome晶格上补偿二维三角形AFM结构存在XMCD信号。计算结果揭示了XMCD光谱与自旋手性符号之间的完全对应关系：仅当自旋手性为负时，XMCD信号才会出现。这种XMCD信号源于三个子晶格不同的吸收系数，这些吸收系数反映了不同的电荷密度各向异性以及自旋和轨道磁矩的方向。
