scholarly journals Pinning Effects of Exchange and Magnetocrystalline Anisotropies on Skyrmion Lattice

2021 ◽  
Vol 9 ◽  
Author(s):  
Xuejin Wan ◽  
Yangfan Hu ◽  
Zhipeng Hou ◽  
Biao Wang
Keyword(s):  
Fourth Order ◽  
Magnetocrystalline Anisotropy ◽  
Sixth Order ◽  
Combined Effects ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Exchange Anisotropy ◽  
Hexagonal Symmetry ◽  
Intrinsic Anisotropy ◽  
Crystallographic Axes

Reorientation of skyrmion crystal (SkX) with respect to crystallographic axes is believed to be insensitive to anisotropies of fourth order in spin-orbit coupling, for which sixth order terms are considered for explanation. Here, we show that this is wrong due to an oversimplified assumption that SkX possesses hexagonal symmetry. When the deformation of SkX is taken into account, fourth order anisotropies such as exchange anisotropy and magnetocrystalline anisotropy have pinning (in this work, the word ‘pinning’ refers to the reorientation effects of intrinsic anisotropy terms) effects on SkX. In particular, we reproduce some experiments of MnSi and Fe1−xCoxSi by considering the effect of fourth order magnetocrystalline anisotropy alone. We reproduce the 30∘ rotation of SkX in Cu2OSeO3 by considering the combined effects of the exchange and magnetocrystalline anisotropies. And we use the exchange anisotropy to explain the reorientation of SkX in VOSe2O5.

Anisotropic Spin-Orbit Coupling and Magnetocrystalline Anisotropy in Vicinal Co Films

2001 ◽  
Vol 87 (6) ◽  
Author(s):  
Sarnjeet S. Dhesi ◽  
Gerrit van der Laan ◽  
Esther Dudzik ◽  
Alexander B. Shick
Keyword(s):  
Magnetocrystalline Anisotropy ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

scholarly journals Direct evidence of interaction-induced Dirac cones in a monolayer silicene/Ag(111) system

2016 ◽  
Vol 113 (51) ◽  
pp. 14656-14661 ◽  
Author(s):  
Ya Feng ◽  
Defa Liu ◽  
Baojie Feng ◽  
Xu Liu ◽  
Lin Zhao ◽  
...  
Keyword(s):  
Brillouin Zone ◽  
Direct Evidence ◽  
Honeycomb Structure ◽  
Low Energy ◽  
Combined Effects ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Dirac Cone ◽  
Unique Type ◽  
Quantum Phenomena

Silicene, analogous to graphene, is a one-atom-thick 2D crystal of silicon, which is expected to share many of the remarkable properties of graphene. The buckled honeycomb structure of silicene, along with enhanced spin-orbit coupling, endows silicene with considerable advantages over graphene in that the spin-split states in silicene are tunable with external fields. Although the low-energy Dirac cone states lie at the heart of all novel quantum phenomena in a pristine sheet of silicene, a hotly debated question is whether these key states can survive when silicene is grown or supported on a substrate. Here we report our direct observation of Dirac cones in monolayer silicene grown on a Ag(111) substrate. By performing angle-resolved photoemission measurements on silicene(3 × 3)/Ag(111), we reveal the presence of six pairs of Dirac cones located on the edges of the first Brillouin zone of Ag(111), which is in sharp contrast to the expected six Dirac cones centered at the K points of the primary silicene(1 × 1) Brillouin zone. Our analysis shows clearly that the unusual Dirac cone structure we have observed is not tied to pristine silicene alone but originates from the combined effects of silicene(3 × 3) and the Ag(111) substrate. Our study thus identifies the case of a unique type of Dirac cone generated through the interaction of two different constituents. The observation of Dirac cones in silicene/Ag(111) opens a unique materials platform for investigating unusual quantum phenomena and for applications based on 2D silicon systems.

Impact of Inter-site Spin–Orbit Coupling on Perpendicular Magnetocrystalline Anisotropy in Cobalt-Based Thin Films

2020 ◽  
Vol 89 (11) ◽  
pp. 114710
Author(s):  
Thi Phuong Thao Nguyen ◽  
Kunihiko Yamauchi ◽  
Kohji Nakamura ◽  
Tamio Oguchi
Keyword(s):  
Thin Films ◽  
Magnetocrystalline Anisotropy ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

scholarly journals Design and realization of topological Dirac fermions on a triangular lattice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maximilian Bauernfeind ◽  
Jonas Erhardt ◽  
Philipp Eck ◽  
Pardeep K. Thakur ◽  
Judith Gabel ◽  
...  
Keyword(s):  
Triangular Lattice ◽  
Quantum Spin ◽  
Spin Orbit Coupling ◽  
Dirac Fermions ◽  
Spin Orbit ◽  
Hexagonal Symmetry ◽  
Tunneling Microscopy ◽  
Heavy Atoms ◽  
Strong Spin ◽  
Quantum Spin Hall

AbstractLarge-gap quantum spin Hall insulators are promising materials for room-temperature applications based on Dirac fermions. Key to engineer the topologically non-trivial band ordering and sizable band gaps is strong spin-orbit interaction. Following Kane and Mele’s original suggestion, one approach is to synthesize monolayers of heavy atoms with honeycomb coordination accommodated on templates with hexagonal symmetry. Yet, in the majority of cases, this recipe leads to triangular lattices, typically hosting metals or trivial insulators. Here, we conceive and realize “indenene”, a triangular monolayer of indium on SiC exhibiting non-trivial valley physics driven by local spin-orbit coupling, which prevails over inversion-symmetry breaking terms. By means of tunneling microscopy of the 2D bulk we identify the quantum spin Hall phase of this triangular lattice and unveil how a hidden honeycomb connectivity emerges from interference patterns in Bloch px ± ipy-derived wave functions.

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