Sohn C H, Kim C H, Sandilands L J, Hien N T M, Kim S Y, Park H J, Kim K W, Moon S J, Yamaura J, Hiroi Z, Noh T W
Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-742, Republic of Korea.
Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Republic of Korea.
Phys Rev Lett. 2017 Mar 17;118(11):117201. doi: 10.1103/PhysRevLett.118.117201. Epub 2017 Mar 13.
Spin-phonon coupling mediated by single ion anisotropy was investigated using optical spectroscopy and first-principles calculations in the all-in-all-out pyrochlore magnet Cd_{2}Os_{2}O_{7}. Clear anomalies were observed in both the phonon frequencies and linewidths at the magnetic ordering temperature. The renormalization of the phonon modes was exceptionally large, signifying the presence of an unconventional magnetoelastic term from large spin-orbit coupling. In addition, the relative phonon frequency shifts show a strong correlation with the modulation of noncubic crystal field by the corresponding lattice distortion. Our observation establishes a new type of spin-phonon coupling through single ion anisotropy, a second-order spin-orbit coupling term, in Cd_{2}Os_{2}O_{7}.
利用光谱学和第一性原理计算，研究了全进全出型烧绿石磁体Cd₂Os₂O₇中由单离子各向异性介导的自旋-声子耦合。在磁有序温度下，声子频率和线宽均出现明显异常。声子模式的重整化异常大，这表明存在来自大自旋-轨道耦合的非常规磁弹项。此外，相对声子频率偏移与相应晶格畸变对非立方晶体场的调制呈现出强相关性。我们的观察结果在Cd₂Os₂O₇中建立了一种通过单离子各向异性（一种二阶自旋-轨道耦合项）的新型自旋-声子耦合。
