Edwards Brendan, Deaconu Darius-A, Murgatroyd Philip A E, Buchberger Sebastian, Antonelli Tommaso, Halliday Daniel, Siemann Gesa-R, Zivanovic Andela, Trzaska Liam, Rajan Akhil, Abarca Morales Edgar, Mayoh Daniel A, Hall Amelia E, Belosludov Rodion V, Watson Matthew D, Kim Timur K, Biswas Deepnarayan, Lee Tien-Lin, Polley Craig M, Carbone Dina, Leandersson Mats, Balakrishnan Geetha, Bahramy Mohammad Saeed, King Phil D C
SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, U.K.
Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
Chem Mater. 2024 Jul 23;36(15):7117-7126. doi: 10.1021/acs.chemmater.4c00824. eCollection 2024 Aug 13.
The addition of metal intercalants into the van der Waals gaps of transition metal dichalcogenides has shown great promise as a method for controlling their functional properties. For example, chiral helimagnetic states, current-induced magnetization switching, and a giant valley-Zeeman effect have all been demonstrated, generating significant renewed interest in this materials family. Here, we present a combined photoemission and density-functional theory study of three such compounds: , , and , to investigate chemical trends of the intercalant species on their bulk and surface electronic structure. Our resonant photoemission measurements indicate increased hybridization with the itinerant NbS-derived conduction states with increasing atomic number of the intercalant, leading to pronounced mixing of the nominally localized intercalant states at the Fermi level. Using spatially and angle-resolved photoemission spectroscopy, we show how this impacts surface-termination-dependent charge transfers and leads to the formation of new dispersive states of mixed intercalant-Nb character at the Fermi level for the intercalant-terminated surfaces. This provides an explanation for the origin of anomalous states previously reported in this family of compounds and paves the way for tuning the nature of the magnetic interactions in these systems control of the hybridization of the magnetic ions with the itinerant states.
在过渡金属二硫属化物的范德华间隙中添加金属嵌入剂，作为一种控制其功能特性的方法已显示出巨大潜力。例如，手性螺旋磁态、电流诱导的磁化翻转以及巨大的谷塞曼效应都已得到证实，这使得人们对这个材料家族重新产生了浓厚兴趣。在这里，我们对三种这样的化合物（ 、 和 ）进行了光电子能谱和密度泛函理论的联合研究，以探究嵌入剂物种对其体相和表面电子结构的化学趋势。我们的共振光电子能谱测量结果表明，随着嵌入剂原子序数的增加，与巡游性的源自NbS的导带态的杂化增强，导致在费米能级处名义上局域的嵌入剂态发生明显混合。利用空间分辨和角分辨光电子能谱，我们展示了这如何影响依赖于表面终止的电荷转移，并导致在嵌入剂终止的表面的费米能级处形成具有混合嵌入剂 - Nb特征的新的色散态。这为先前在这类化合物中报道的异常态的起源提供了解释，并为通过控制磁性离子与巡游态的杂化来调节这些系统中的磁相互作用性质铺平了道路。
