Theoretical Study of Surface Electronic States of Layered Transition-Metal Dichalcogenides and Scanning Tunneling Spectroscopy

层状过渡金属二硫属化物表面电子态理论研究及扫描隧道光谱

基本信息

批准号：
63540250
负责人：
SUZUKI Naoshi
金额：
$ 0.83万
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：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

As a first step toward obtaining surface electronic states or electronic states of a slab of layered transition-metal dichalcogenides TX_2 (T:transition-metal atoms, X:chalcogen atoms), we have calculated the bulk electronic band structures of TX_2 itself and its transition-metal intercalation compounds.We first calculated the bulk electronic band structures of 1T-TiS_2, 1T-TiSe_2, 2H-TaS_2 and 2H-NbS_2 on the basis of the APW method with use of the muffin-tin (MT) approximation. As the result it has been clarified that corrections to the MT approximation are very important for these materials because of their strong anisotropic nature. It has been also clarified that in order to make correction to the MT approximation we have to use linearized methods of the band calculation such as the LAPW method because of a problem of computing time, in particular when calculating the electronic band structures of systems containing many atoms in the unit cell.Next, by using the LAPW method we calculated the electronic band structures of transition-metal intercalation compounds of 2H-TaS_2, Mn_<1/4>TaS_2, which has 26 atoms in the unit cell. The band structures obtained for the non-magnetic states have clearly shown that the localized moment model for the Mn 3d electrons and the rigid band model for intercalation effects are not valid. Further the magnitude of the magnetic moment per Mn atom evaluated from the band calculation for the ferromagnetic states is in good agreement with the observation. Thus it has been clarified that the magnetic properties of Mn_<1/4>TaS_2 can be understood from the view point of itinerant Mn 3d electrons.We are now developing LAPW computer programs for making corrections to the MT approximation and for calculating electronic structures of a slab of TX_2.

作为获取表面电子状态或电子状态的第一步2H-TAS_2和2H-NBS_2基于APW方法，使用松饼键（MT）近似。结果，已经澄清了MT近似的校正对于这些材料的强烈各向异性性质非常重要。还可以澄清的是，要对MT近似进行校正，我们必须使用频带计算的线性化方法，例如LAPW方法，因为计算时间问题，尤其是在计算单位细胞中包含许多原子的系统结构的系统结构时，使用LAPW方法，我们使用LAPW方法来计算了2个nimel。 Mn_ <1/4> TAS_2，单位单元格中有26个原子。非磁性状态获得的带结构清楚地表明，MN 3D电子的局部力矩模型和互插效应的刚性带模型无效。进一步，从频带计算的铁磁态评估的每Mn原子的磁矩的大小与观察结果非常吻合。因此，已经澄清的是，从巡回MN 3D电子的角度可以理解Mn_ <1/4> TAS_2的磁性特性。我们现在正在开发LAPW计算机程序，以对MT近似和计算TX_2平板的电子结构进行校正。