Effects of spin-orbit coupling on magnetic properties of discrete and extended magnetic systems

2008 ◽  
Vol 29 (13) ◽  
pp. 2187-2209 ◽  
Author(s):  
Dadi Dai ◽  
Hongjun Xiang ◽  
Myung-Hwan Whangbo
Keyword(s):  
Magnetic Properties ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Magnetic Systems

scholarly journals Electronic and magnetic properties of two dimensional crystals

2021 ◽  
Author(s):  
◽  
Hani Hatami
Keyword(s):  
Magnetic Properties ◽  
Transport Properties ◽  
Energy Levels ◽  
Bilayer Graphene ◽  
Orbit Coupling ◽  
Monolayer Graphene ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Electronic And Magnetic Properties

<p>In the last few years, two dimensional crystals have become available for experimental studies. Good examples of such systems are monolayers and bilayers of graphene and monolayers of transition metal dichalcogenides such as MoS₂ and WSe₂. The availability of two dimensional crystals has encouraged physicists to study the electronic and magnetic properties of such systems. This thesis adds to the theoretical knowledge about electronic and magnetic properties of two dimensional crystals with the focus on graphene and MoS₂.  As a general theme in this thesis, we calculate how in general these systems interact with electric and magnetic fields and what their response is to such stimuli. In particular, we have studied the response of monolayer graphene to an in-plane electric field. We have also looked at spin-orbit coupling effects that arise from applying perpendicular or in-plane external electric fields, especially their consequences for transport properties of bilayer graphene. We investigated the electronic properties of charge carriers confined in a mesoscopic ring structure using a gate voltage in bilayer graphene. We also showed how spin-orbit coupling can affect the electrical properties of such rings. We found how spin-orbit coupling can affect the transport properties in bilayer graphene. We also investigated the RKKY or indirect exchange coupling between magnetic moments in monolayer MoS₂ through calculating wave vector dependent spin susceptibility.  We examined the electronic properties of electrons and holes confined electrostatically into a bilayer graphene ring. We presented an analytical solution for finding energy levels in the ring. We showed that the magnetic field dependence of the lowest energy level with fixed angular momentum in bilayer graphene rings, in contrast to usual semiconductor quantum rings, is not parabolic but displays an asymmetric “Mexican hat“. We found that introducing spin-orbit coupling in the ring can flatten this Mexican hat.  We studied the effect of an orbital Rashba type effect, induced by an in-plane electric field in monolayer graphene. Using perturbation theory, we showed that this term can affect the energy levels in a crossed electric and magnetic field such that the electron and hole levels repel each other. We calculated the AC transport of monolayer graphene in the linear-response regime and showed that taking the orbital Rashba term into account casts doubt on the universality of the minimum conductivity of monolayer graphene.  We studied the effect of spin-orbit coupling in transport properties of bilayer graphene systems by calculating tunnelling through npn and np junctions. We showed that at sufficiently large spin-orbit strength, normal transmission through a barrier which is forbidden in bilayer graphene becomes finite. We predict that in a weak Rashba spin-orbit regime, outgoing electrons show signals which are spin polarized. We also showed that considering spin-orbit coupling only in the barrier of an npn junction can invert the spin of the incoming electrons.  Finally, we obtained analytical expressions for the wave vector-dependent static spin susceptibility of monolayer transition metal dichalcogenides, considering both the electron-doped and hole-doped cases. These results are then applied to the calculations of physical observables of monolayer MoS₂. We claculated that the hole-mediated RKKY exchange interaction for in-plane impurity-spin components decays with a different power law from what is expected for a two-dimensional Fermi liquid. In contrast, we calculated that the out-of-plane spin response shows the conventional long-range behaviour.</p>

Influence of spin-orbit coupling on the transport and magnetic properties ofCo3Pd97

1995 ◽  
Vol 52 (1) ◽  
pp. 335-342 ◽  
Author(s):  
P. A. Stampe ◽  
H. P. Kunkel ◽  
Z. Wang ◽  
G. Williams
Keyword(s):  
Magnetic Properties ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

scholarly journals Twisted magnetization phases in orbital-dominant rare-earth nitrides

2021 ◽  
Author(s):  
◽  
James McNulty
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Orbit Coupling ◽  
Ferromagnetic Semiconductors ◽  
Spin Moment ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Orbital Moment ◽  
Orbital Contribution ◽  
Rare Earth Nitrides

<p>In this thesis we investigate the magnetic properties of NdN and SmN, members of the rare-earth nitrides, a series of intrinsic ferromagnetic semiconductors. In rare-earth systems, the strong spin-orbit coupling of the partially filled 4ƒ shell ensures that there is a substantial orbital contribution to the ferromagnetic moment, in contrast to many transition metal systems where the orbital moment is usually quenched. In SmN and NdN the orbital moment actually exceeds the spin moment, and the resulting orbital dominant magnetization allows for the fabrication of a magnetic heterostructures showing novel behavior.  We report a new theoretical study of the magnetic properties on both SmN and NdN by considering the atomic-like 4ƒ electrons. These calculations incorporate spin-orbit coupling, the exchange interaction in a self-consistent mean-field approach, and crystal field interactions in an arbitrary-multiplet point-charge model. Our findings show excellent agreement with the experimentally measured ferromagnetic moments of SmN and NdN, representing an advance from previous theoretical studies.  We also report an experimental study on SmN/GdN heterostructures using the element-resolved method of x-ray magnetic circular dichroism (XMCD) to probe the magnetism. The competition between the orbital-dominant Zeeman coupling in SmN and the ferromagnetic spin-based interface exchange with GdN, which has purely a spin moment, results in a twisted magnetization profile. The depth profile of the magnetization derived from XMCD measurements showed good agreement with an analytical model developed to describe the competing interactions.  In a second study, a superlattice of NdN/GdN was investigated via XMCD and standard magnetometry techniques. A twisted magnetization was shown to be present due to the same mechanism as in the SmN/GdN system. By varying the maximum applied field and temperature, twisted phases were shown to develop in both GdN and NdN layers. These twisted phases in orbital-dominant ferromagnetic semiconductors represent a departure from previously explored spin-dominant metallic systems displaying similar twisted phases.</p>

Covalent states and spin-orbit coupling in electronic and magnetic properties of Ba6Y2Rh2Ti2O17

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
Jihai Yu ◽  
Lin Wu ◽  
Di Wang ◽  
Qingfang Li ◽  
Weifeng Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Electronic And Magnetic Properties

Ab initio studies of electric field gradients and magnetic properties of uranium dipnicties

RSC Advances ◽  
2015 ◽  
Vol 5 (47) ◽  
pp. 37592-37602 ◽  
Author(s):  
E. Ghasemikhah ◽  
S. Jalali Asadabadi ◽  
Iftikhar Ahmad ◽  
M. Yazdani-Kacoei
Keyword(s):  
Magnetic Properties ◽  
Electric Field ◽  
Ab Initio ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Electric Field Gradients ◽  
Field Gradients

In this paper, we explore the electric field gradients (EFGs) at 238U sites for antiferromagnetic UX2 (X = P, As, Sb, Bi) dipnicties using LDA, LDA + U, GGA, GGA + U, and EECE schemes in the presence of spin–orbit coupling.

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