scholarly journals Giant Dzyaloshinskii-Moriya interaction in Rashba superlattices

2020 ◽  
Author(s):  
Woo-Seung Ham ◽  
Abdul-Muizz Pradipto ◽  
Kay Yakushiji ◽  
Kwangsu Kim ◽  
Sonny Rhim ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Material Design ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Band Formation ◽  
Stacking Order ◽  
Magnetic Skyrmions ◽  
Moriya Interaction

Abstract Dzyaloshinskii-Moriya interaction (DMI) is considered as one of the most important energy for specific chiral texture such as magnetic skyrmions. The key of generating DMI is absence of structural inversion symmetry and exchange energy with spin-orbit coupling. Therefore, a vast majority of researches about DMI is mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report that asymmetric band formation in an artificial superlattice arises from inversion symmetry breaking in stacking order of atomic layers, resulting in bulk DMI. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin-orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Such Rashba superlattices can be a new class of material design for spintronics applications.

scholarly journals Dzyaloshinskii–Moriya interaction in noncentrosymmetric superlattices

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Woo Seung Ham ◽  
Abdul-Muizz Pradipto ◽  
Kay Yakushiji ◽  
Kwangsu Kim ◽  
Sonny H. Rhim ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Degrees Of Freedom ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Band Formation ◽  
Research Activities ◽  
Moriya Interaction

AbstractDzyaloshinskii–Moriya interaction (DMI) is considered as one of the most important energies for specific chiral textures such as magnetic skyrmions. The keys of generating DMI are the absence of structural inversion symmetry and exchange energy with spin–orbit coupling. Therefore, a vast majority of research activities about DMI are mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report an asymmetric band formation in a superlattices (SL) which arises from inversion symmetry breaking in stacking order of atomic layers, implying the role of bulk-like contribution. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin–orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Our work provides more degrees of freedom to design chiral magnets for spintronics applications.

scholarly journals Spin–Orbit Effects in CoFeB/MgO Heterostructures with Heavy Metal Underlayers

SPIN ◽  
2016 ◽  
Vol 06 (02) ◽  
pp. 1640002 ◽  
Author(s):  
Jacob Torrejon ◽  
Junyeon Kim ◽  
Jaivardhan Sinha ◽  
Masamitsu Hayashi
Keyword(s):  
Heavy Metal ◽  
Transition Metals ◽  
Magnetic Anisotropy ◽  
Metal Layer ◽  
Perpendicular Magnetic Anisotropy ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Moriya Interaction ◽  
Strong Spin

We study effects originating from the strong spin–orbit coupling in CoFeB/MgO heterostructures with heavy metal (HM) underlayers. The perpendicular magnetic anisotropy at the CoFeB/MgO interface, the spin Hall angle of the heavy metal layer, current induced torques and the Dzyaloshinskii–Moriya interaction at the HM/CoFeB interfaces are studied for films in which the early 5[Formula: see text] transition metals are used as the HM underlayer. We show how the choice of the HM layer influences these intricate spin–orbit effects that emerge within the bulk and at interfaces of the heterostructures.

scholarly journals Electronically driven spin-reorientation transition of the correlated polar metal Ca3Ru2O7

2020 ◽  
Vol 117 (27) ◽  
pp. 15524-15529 ◽  
Author(s):  
Igor Marković ◽  
Matthew D. Watson ◽  
Oliver J. Clark ◽  
Federico Mazzola ◽  
Edgar Abarca Morales ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Sudden Onset ◽  
Spin Reorientation ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Large Hole ◽  
Electronic Correlations ◽  
Spin Reorientation Transition

The interplay between spin–orbit coupling and structural inversion symmetry breaking in solids has generated much interest due to the nontrivial spin and magnetic textures which can result. Such studies are typically focused on systems where large atomic number elements lead to strong spin–orbit coupling, in turn rendering electronic correlations weak. In contrast, here we investigate the temperature-dependent electronic structure ofCa3Ru2O7, a4doxide metal for which both correlations and spin–orbit coupling are pronounced and in which octahedral tilts and rotations combine to mediate both global and local inversion symmetry-breaking polar distortions. Our angle-resolved photoemission measurements reveal the destruction of a large hole-like Fermi surface upon cooling through a coupled structural and spin-reorientation transition at 48 K, accompanied by a sudden onset of quasiparticle coherence. We demonstrate how these result from band hybridization mediated by a hidden Rashba-type spin–orbit coupling. This is enabled by the bulk structural distortions and unlocked when the spin reorients perpendicular to the local symmetry-breaking potential at the Ru sites. We argue that the electronic energy gain associated with the band hybridization is actually the key driver for the phase transition, reflecting a delicate interplay between spin–orbit coupling and strong electronic correlations and revealing a route to control magnetic ordering in solids.

scholarly journals Absence of the Rashba Splitting of Au(111) Surface Bands

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
I. N. Yakovkin
Keyword(s):  
Electronic Structure ◽  
Dft Calculations ◽  
Surface States ◽  
Orbit Coupling ◽  
Spin Splitting ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Relativistic Approximation ◽  
Photoemission Experiment

The electronic structure of Au(111) films is studied by means of relativistic DFT calculations. It is found that the twinning of the surface bands, observed in photoemission experiment, does not necessarily correspond to the spin-splitting of the surface states caused by the break of the inversion symmetry at the surface. The twinning of the bands of clean Au(111) films can be obtained within nonrelativistic or scalar-relativistic approximation, so that it is not a result of spin-orbit coupling. However, the spin-orbit coupling does not lead to the spin-splitting of the surface bands. This result is explained by Kramers’ degeneracy, which means that the existence of a surface itself does not destroy the inversion symmetry of the system. The inversion symmetry of the Au(111) film can be broken, for example, by means of adsorption, and a hydrogen monolayer deposited on one face of the film indeed leads to the appearance of the spin-splitting of the bands.

scholarly journals First-principles Dzyaloshinskii–Moriya interaction in a non-collinear framework

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. Cardias ◽  
A. Szilva ◽  
M. M. Bezerra-Neto ◽  
M. S. Ribeiro ◽  
A. Bergman ◽  
...  
Keyword(s):  
First Principles ◽  
Real Space ◽  
Orbit Coupling ◽  
Magnetic Configuration ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Atomic Sphere ◽  
Sphere Approximation ◽  
Atomic Sphere Approximation ◽  
Moriya Interaction

AbstractWe have derived an expression of the Dzyaloshinskii–Moriya interaction (DMI), where all the three components of the DMI vector can be calculated independently, for a general, non-collinear magnetic configuration. The formalism is implemented in a real space—linear muffin-tin orbital—atomic sphere approximation (RS-LMTO-ASA) method. We have chosen the Cr triangular trimer on Au(111) and Mn triangular trimers on Ag(111) and Au(111) surfaces as numerical examples. The results show that the DMI (module and direction) is drastically different between collinear and non-collinear states. Based on the relation between the spin and charge currents flowing in the system and their coupling to the non-collinear magnetic configuration of the triangular trimer, we demonstrate that the DMI interaction can be significant, even in the absence of spin-orbit coupling. This is shown to emanate from the non-collinear magnetic structure, that can induce significant spin and charge currents even with spin-orbit coupling is ignored.

scholarly journals Optical spin–orbit coupling in the presence of magnetization: photonic skyrmion interaction with magnetic domains

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xinrui Lei ◽  
Luping Du ◽  
Xiaocong Yuan ◽  
Anatoly V. Zayats
Keyword(s):  
Electromagnetic Waves ◽  
Magnetic Domain ◽  
Light Polarization ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Magnetic Domains ◽  
Spin Distribution ◽  
Magnetic Skyrmions ◽  
Almost All

Abstract Polarization and related spin properties are important characteristics of electromagnetic waves and their manipulation is crucial in almost all photonic applications. Magnetic materials are often used for controlling light polarization through the magneto-optical Kerr or Faraday effects. Recently, complex topological structures of the optical spin have been demonstrated in the evanescent light field, which in the presence of the spin–orbit coupling may form photonic skyrmions. Here, we investigate the optical spin–orbit coupling in the presence of magnetization and the interaction between photonic skyrmions and magnetic domains. We demonstrate that the magnetization is responsible for the modulation of the optical spin distribution, resulting in twisted Neel-type skyrmions. This effect can be used for the visualization of magnetic domain structure with both in plane and polar orientation of magnetization, and in turn for creation of complex optical spin distributions using magnetization patterns. The demonstrated interplay between photonic skyrmions and magneto-optical effects may also provide novel opportunities for investigation and manipulation of magnetic skyrmions using optical spin–orbit coupling.

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