Xie Lilia S, Gonzalez Oscar, Li Kejun, Michiardi Matteo, Gorovikov Sergey, Ryu Sae Hee, Fender Shannon S, Zonno Marta, Jo Na Hyun, Zhdanovich Sergey, Jozwiak Chris, Bostwick Aaron, Husremović Samra, Erodici Matthew P, Mollazadeh Cameron, Damascelli Andrea, Rotenberg Eli, Ping Yuan, Bediako D Kwabena
Department of Chemistry, University of California, Berkeley, California 94720, United States.
Department of Physics, University of California, Santa Cruz, California 95064, United States.
Chem Mater. 2023 Aug 16;35(17):7239-7251. doi: 10.1021/acs.chemmater.3c01564. eCollection 2023 Sep 12.
Magnetic materials with noncollinear spin textures are promising for spintronic applications. To realize practical devices, control over the length and energy scales of such spin textures is imperative. The chiral helimagnets CrNbS and CrTaS exhibit analogous magnetic-phase diagrams with different real-space periodicities and field dependence, positioning them as model systems for studying the relative strengths of the microscopic mechanisms giving rise to exotic spin textures. Although the electronic structure of the Nb analogue has been experimentally investigated, the Ta analogue has received far less attention. Here, we present a comprehensive suite of electronic structure studies on both CrNbS and CrTaS using angle-resolved photoemission spectroscopy and density functional theory. We show that bands in CrTaS are more dispersive than their counterparts in CrNbS, resulting in markedly different Fermi wavevectors. The fact that their qualitative magnetic phase diagrams are nevertheless identical shows that hybridization between the intercalant and host lattice mediates the magnetic exchange interactions in both of these materials. We ultimately find that ferromagnetic coupling is stronger in CrTaS, but larger spin-orbit coupling (and a stronger Dzyaloshinskii-Moriya interaction) from the heavier host lattice ultimately gives rise to shorter spin textures.
具有非共线自旋纹理的磁性材料在自旋电子学应用中颇具前景。为了实现实际应用的器件，控制此类自旋纹理的长度和能量尺度至关重要。手性螺旋磁体CrNbS和CrTaS展现出具有不同实空间周期性和场依赖性的类似磁相图，这使它们成为研究产生奇异自旋纹理的微观机制相对强度的模型系统。尽管已对Nb类似物的电子结构进行了实验研究，但Ta类似物受到的关注要少得多。在此，我们使用角分辨光电子能谱和密度泛函理论，对CrNbS和CrTaS进行了一套全面的电子结构研究。我们表明，CrTaS中的能带比CrNbS中的能带更具色散性，导致费米波矢明显不同。然而，它们定性的磁相图相同这一事实表明，插层剂与主体晶格之间的杂化介导了这两种材料中的磁交换相互作用。我们最终发现，CrTaS中的铁磁耦合更强，但较重主体晶格产生的更大自旋轨道耦合（以及更强的Dzyaloshinskii-Moriya相互作用）最终导致自旋纹理更短。
