scholarly journals Phase shift in skyrmion crystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Satoru Hayami ◽  
Tsuyoshi Okubo ◽  
Yukitoshi Motome
Keyword(s):  
Phase Shift ◽  
Relative Phase ◽  
Exchange Interactions ◽  
Thermal Fluctuations ◽  
Coupled Systems ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Density Waves ◽  
Vortex Crystal ◽  
Spin Texture

AbstractThe magnetic skyrmion crystal is a periodic array of a swirling topological spin texture. Since it is regarded as an interference pattern by multiple helical spin density waves, the texture changes with the relative phase shifts among the constituent waves. Although such a phase degree of freedom is relevant to not only magnetism but also transport properties, its effect has not been elucidated thus far. We here theoretically show that a phase shift in the skyrmion crystals leads to a tetra-axial vortex crystal and a meron-antimeron crystal, both of which show a staggered pattern of the scalar spin chirality and give rise to nonreciprocal transport phenomena without the spin-orbit coupling. We demonstrate that such a phase shift can be driven by exchange interactions between the localized spins, thermal fluctuations, and long-range chirality interactions in spin-charge coupled systems. Our results provide a further diversity of topological spin textures and open a new field of emergent electromagnetism by the phase shift engineering.

scholarly journals Heisenberg and anisotropic exchange interactions in magnetic materials with correlated electronic structure and significant spin-orbit coupling

2021 ◽  
Vol 103 (17) ◽  
Author(s):  
Vladislav Borisov ◽  
Yaroslav O. Kvashnin ◽  
Nikolaos Ntallis ◽  
Danny Thonig ◽  
Patrik Thunström ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Magnetic Materials ◽  
Exchange Interactions ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Anisotropic Exchange

SPIN-DEPENDENT ELECTRON TRANSPORT THROUGH A THREE-TERMINAL MESOSCOPIC SPIN-ORBIT COUPLED SYSTEMS

2013 ◽  
Vol 27 (07) ◽  
pp. 1361003
Author(s):  
ZHONGHUI XU ◽  
XIANBO XIAO ◽  
YUGUANG CHEN
Keyword(s):  
Electron Transport ◽  
Spin Polarization ◽  
Function Method ◽  
Structural Parameters ◽  
Coupled Systems ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Wide Region ◽  
Rashba Spin ◽  
Electron Transport Properties

We studied theoretically the spin-dependent electron transport properties of a three-terminal nanostructure proposed by Xiao and Chen [J. Appl. Phys.1, 108 (2010)]. The spin-resolved recursive Green's function method is used to calculate the three-terminal spin-polarization. We focus on the influence both of the structural parameters and Rashba spin–orbit coupling (SOC) strength in the investigated system. It is shown that the spin-polarization is still a reasonable value for being observable in experiment with small Rashba SOC strength and longer length of the wide region in the investigated system. The underlying physics is revealed to originate from the effect of SOC-induced effective magnetic field at the structure-induced Fano resonance. This length of the middle wide region in three-terminal nanostructure can be more easily fabricated experimentally.

scholarly journals Low-field Magnetic Anisotropy of Sr2IrO4

2022 ◽  
Author(s):  
Muhammad Nauman ◽  
Tayyaba Hussain ◽  
Joonyoung Choi ◽  
Nara Lee ◽  
Young Jai Choi ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Exchange Interaction ◽  
Exchange Interactions ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Easy Magnetization ◽  
Magnetic Exchange ◽  
Crystal Field Effect ◽  
Out Of Plane

Abstract Magnetic anisotropy in strontium iridate (Sr2IrO4) is essential because of its strong spin–orbit coupling and crystal field effect. In this paper, we present a detailed mapping of the out-of-plane (OOP) magnetic anisotropy in Sr2IrO4 for different sample orientations using torque magnetometry measurements in the low-magnetic-field region before the isospins are completely ordered. Dominant in-plane anisotropy was identified at low fields, confirming the b axis as an easy magnetization axis. Based on the fitting analysis of the strong uniaxial magnetic anisotropy, we observed that the main anisotropic effect arises from a spin–orbit-coupled magnetic exchange interaction affecting the OOP interaction. The effect of interlayer exchange interaction results in additional anisotropic terms owing to the tilting of the isospins. The results are relevant for understanding OOP magnetic anisotropy and provide a new way to analyze the effects of spin–orbit-coupling and interlayer magnetic exchange interactions. This study provides insight into the understanding of bulk magnetic, magnetotransport, and spintronic behavior on Sr2IrO4 for future studies.

scholarly journals Unconventional supercurrent phase in Ising superconductor Josephson junction with atomically thin magnetic insulator

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
H. Idzuchi ◽  
F. Pientka ◽  
K.-F. Huang ◽  
K. Harada ◽  
Ö. Gül ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Orbit Coupling ◽  
Cooper Pairs ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Magnetic Domains ◽  
Magnetic Exchange ◽  
Spin Texture ◽  
Magnetic Insulator ◽  
Opening Up

AbstractIn two-dimensional (2D) NbSe2 crystal, which lacks inversion symmetry, strong spin-orbit coupling aligns the spins of Cooper pairs to the orbital valleys, forming Ising Cooper pairs (ICPs). The unusual spin texture of ICPs can be further modulated by introducing magnetic exchange. Here, we report unconventional supercurrent phase in van der Waals heterostructure Josephson junctions (JJs) that couples NbSe2 ICPs across an atomically thin magnetic insulator (MI) Cr2Ge2Te6. By constructing a superconducting quantum interference device (SQUID), we measure the phase of the transferred Cooper pairs in the MI JJ. We demonstrate a doubly degenerate nontrivial JJ phase (ϕ), formed by momentum-conserving tunneling of ICPs across magnetic domains in the barrier. The doubly degenerate ground states in MI JJs provide a two-level quantum system that can be utilized as a new dissipationless component for superconducting quantum devices. Our work boosts the study of various superconducting states with spin-orbit coupling, opening up an avenue to designing new superconducting phase-controlled quantum electronic devices.

scholarly journals Gate controlled anomalous phase shift in Al/InAs Josephson junctions

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
William Mayer ◽  
Matthieu C. Dartiailh ◽  
Joseph Yuan ◽  
Kaushini S. Wickramasinghe ◽  
Enrico Rossi ◽  
...  
Keyword(s):  
Phase Shift ◽  
Josephson Junction ◽  
Phase Difference ◽  
Josephson Junctions ◽  
Quantum Interference ◽  
Josephson Effect ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Superconducting Quantum Interference Device

AbstractIn a standard Josephson junction the current is zero when the phase difference between superconducting leads is zero. This condition is protected by parity and time-reversal symmetries. However, the combined presence of spin–orbit coupling and magnetic field breaks these symmetries and can lead to a finite supercurrent even when the phase difference is zero. This is the so called anomalous Josephson effect—the hallmark effect of superconducting spintronics—which can be characterized by the corresponding anomalous phase shift. Here we report the observation of a tunable anomalous Josephson effect in InAs/Al Josephson junctions measured via a superconducting quantum interference device. By gate controlling the density of InAs, we are able to tune the spin–orbit coupling in the Josephson junction. This gives us the ability to tune the anomalous phase, and opens new opportunities for superconducting spintronics, and new possibilities for realizing and characterizing topological superconductivity.

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