Terahertz Magneto-Optical Excitations of the sd-Hybrid States of Lithium Nitridocobaltate Li2(Li1-xCox)N.
Terahertz Magneto-Optical Excitations of the sd-Hybrid States of Lithium Nitridocobaltate Li2(Li1-xCox)N.
复制标题
氮化钴酸锂 Li2(Li1-xCox)N sd 杂化态的太赫兹磁光激发
DOI：
10.1021/acs.inorgchem.0c03358
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发表时间：
2021
影响因子：
4.6
通讯作者：
V. Kataev
中科院分区：
文献类型：
--
作者：
C. Albert;T. J. Ballé;F. A. Breitner;Y. Krupskaya;A. Alfonsov;Z. Zangeneh;S. Avdoshenko;M. S. Eldeeb;L. Hozoi;A. Vilangottunjalil;E. Haubold;A. Charnukha;B. Büchner;A. Jesche ;V. Kataev
报道了x=0.005.0 1，0.0 1，0.0 2的共掺氮化锂Li2(Li1-xCOX)N单晶磁各向异性的实验和理论研究结果。最近的研究表明，用3d过渡金属(TM)离子掺杂Li3N晶体基质可以获得与稀土配合物的强各向异性单分子磁性相媲美的优异的磁性能。我们对Li_2(Li_(1-x)COX)_N的电子自旋共振和太赫兹光谱的联合研究使我们能够准确地确定顺磁性Co(I)离子的基态多重态Ŝ=1的自旋能级能量。特别是，我们发现在基态单态和第一激发双重态之间有一个很大的零场分裂(ZF)，几乎为1太赫兹(∼4 meV或33 cm-1)。在计算方面，从头算多重体量子化学计算显示了与实验值一致的零位能隙。如此大的零位能产生非常强的单离子磁各向异性，类似于稀土离子的易平面型。它的微观来源是Li2(Li1-xCOX)N中Co(I)离子与两个氮配体的不寻常的线性配位。我们的计算还证明了电子壳层的强烈3D-4S杂化导致59Co核上显著的电子自旋密度，这可能是实验观察到的ESR信号的超大超精细结构的原因。总之，我们的实验光谱和计算结果使我们能够在微观水平上全面了解Li2[Li1-x(TM)x]N磁体的显著性质。
We report the results of the experimental and theoretical study of the magnetic anisotropy of single crystals of the Co-doped lithium nitride Li2(Li1–xCox)N withx= 0.005, 0.01, and 0.02. It was shown recently that doping of the Li3N crystalline matrix with 3d transition metal (TM) ions yields superior magnetic properties comparable with the strongly anisotropic single-molecule magnetism of rare-earth complexes. Our combined electron spin resonance (ESR) and THz spectroscopic investigations of Li2(Li1–xCox)N in a very broad frequency range up to 1.7 THz and in magnetic fields up to 16 T enable an accurate determination of the energies of the spin levels of the ground state multiplet Ŝ= 1 of the paramagnetic Co(I) ion. In particular, we find a very large zero field splitting (ZFS) of almost 1 THz (∼4 meV or 33 cm–1) between the ground-state singlet and the first excited doublet state. On the computational side,ab initiomany-body quantum chemistry calculations reveal a ZFS gap consistent with the experimental value. Such a large ZFS energy yields a very strong single-ion magnetic anisotropy of easy-plane type resembling that of rare-earth ions. Its microscopic origin is the unusual linear coordination of the Co(I) ions in Li2(Li1–xCox)N with two nitrogen ligands. Our calculations also evidence a strong 3d–4s hybridization of the electronic shells resulting in significant electron spin density at the59Co nuclei, which may be responsible for the experimentally observed extraordinary large hyperfine structure of the ESR signals. Altogether, our experimental spectroscopic and computational results enable comprehensive insights into the remarkable properties of the Li2[Li1–x(TM)x]N magnets on the microscopic level.