Electronic Band Structures and Physical Properties of Intercalation Compounds of Transition-Metal Dichalcogenides

过渡金属二硫化物插层化合物的电子能带结构和物理性质

基本信息

批准号：
61540235
负责人：
SUZUKI Naoshi
金额：
$ 0.77万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61540235/
关键词：
Transition-metal dichalcogenide Intercalation compounds Electronic band structure APW method Bond order Bonding state Antibonding state RKKY相互作用強磁性

项目摘要

Electronic and structures and bonding natures of intercalation compounds of M_xTiS_2 (M=transition metal) are studied on the basis of tne APW band calcuation. RKKY interaction in M_xNbS_2 is also studied by using the realistic band structures of 2H-NbS_2. The main results are summarized as follows.1. Electronic bands and bonding natures of non-magnetic M_xTis_2.(1) On intercalation the M-3d states form a new bands between the Ti-d<gamma> and S-p bonding band and the Ti-d non-bonding band. The Fermi level lies in this new band. The Ti-d<gamma> and S-p components are mixed significantly in this new band and its band width is fairly large.(2) The M-d<gamma> and S-p orbitals make also covalent-like bonds. The d orbitals of Ti and M ions hybridise significantly and form also bonding and anti-bonding states. These results suggest clearly that the so-called rigid-band-model cannot be applied for MxTiS_2 and that the M-od electrons should be treated as itinerant electrons.2. Electronic bonds of ferromagnetic Fe_<1/3>TiS_2 and FeTiS_2.Up- and down-spin bands of Fe 3d components show a large splitting, shich cannot be described as a rigid splitting of the non-magnetic bands. The spin moment is evaluated as 2.55<mu>_B/unit cell in Fe_<1/3>TiS_2 and 3.22<mu>_B/unit cell in FeTiS_2. This result indicate also itinerant character of the M 3d electrons.3. RKKY interaction in M_xNbS_2.Exchange couplings due to RKKY interaction in M_xNbS_2 are calculated on the basis of the rigid-band-model by using the realistic band structures of 2H-NbS_2. When x=1/4, Fourier transform of the exchange couplings takes the almost same extremum at the T and K points, which indicate either ferromagnetic or triangular spin arrangement is likely to be realsized. When x=1/3, the most stable spin arrangement is the antiferromagnetic structure corresponding to the M point which is realized in Co^</3>NbS_2.

根据TNE APW频段计算，研究了M_XTIS_2（M =过渡金属）插入化合物的电子和结构以及键合。还使用2H-NBS_2的逼真的频带结构研究了M_XNBS_2中的rkky互动。主要结果总结如下1。非磁性m_xtis_2的电子带和键合中心。（1）在插入上，M-3D状态在Ti-D <Gamma>和S-P键键和S-P键键之间形成一个新的频段，以及Ti-D非键频带。费米级别在于这个新乐队。 Ti-d <gamma>和S-P分量在这个新频段中显着混合，其带宽相当大。（2）M-D <gamma>和S-P轨道也具有共价键。 Ti和M离子的D轨道显着杂交，并形成键合和反键状态。这些结果清楚地表明，所谓的刚带模型不能用于MXTIS_2，并且应将M-od电子视为巡回电子2。铁磁Fe_ <1/3> Tis_2和Fetis_2.up-下旋转的Fe 3D组件的电子键显示出较大的分裂，Shich不能描述为非磁段的刚性分裂。旋转力矩在Fe_ <1/3> tis_2和3.22 <mu> _b/单位单元格中评估为2.55 <mu> _b/单位单元格。该结果也表明M 3D电子的巡回特征3。通过使用2H-NBS_2的逼真的频段结构，根据刚性波段模式计算M_XNBS_2中由于M_XNBS_2中rkky相互作用而引起的rkky相互作用。当x = 1/4时，交换耦合的傅立叶变换在T和K点处几乎相同，这表明铁磁性或三角形自旋排列可能是实现的。当X = 1/3时，最稳定的自旋排列是与M点相对应的抗磁磁结构，该结构在CO^</3> nbs_2中实现。