Spin-Orbit Coupling Versus Exchange Interaction in Actinide Metals

2008 ◽  
Vol 1104 ◽  
Author(s):  
Gerrit van der Laan ◽  
Kevin Thomas Moore
Keyword(s):  
Orbit Interaction ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Intermediate Coupling ◽  
Sum Rule ◽  
Transmission Electron ◽  
Forbidden Transition ◽  
Rule Analysis ◽  
Electron Energy Loss ◽  
Versus Exchange

AbstractThe electronic structure of the actinide metals, Th, U, Np, Pu, Am, and Cm, is investigated using electron energy-loss spectroscopy (EELS) in a transmission electron microscope, together with many-electron spectral calculations. At the N4,5 edge, sum rule analysis gives the angular part of the spin-orbit interaction per hole, showing that while light metals (Th and U) follow LS coupling, heavier metals (Pu, Am, and Cm) follow intermediate coupling of the 5f states. The intermediate coupling is near the jj limit for Pu and Am, but strongly shifted towards the LS coupling limit for Cm. At the O4,5 edge many-electron spectral calculations show that the prepeak corresponds to a “forbidden” transition.

ROTATIONAL ENERGY LEVELS OF STATES AND INTENSITIES IN TRANSITIONS: APPLICATIONS TO SOME HEAVIER HYDRIDES

1967 ◽  
Vol 45 (8) ◽  
pp. 2581-2596 ◽  
Author(s):  
I. Kopp ◽  
J. T. Hougen
Keyword(s):  
Energy Levels ◽  
Relative Size ◽  
Orbit Interaction ◽  
Spin Splitting ◽  
Energy Separation ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
First Approximation ◽  
Coupling Case ◽  
Π State

Three topics concerning [Formula: see text] states are discussed: (1) The magnitude of the Ω-type splitting in a [Formula: see text] state arising from a Σ state of even multiplicity has been considered and is found to be given to a first approximation by [Formula: see text]. This result leads to the introduction and discussion of a coupling case (a′) for Σ states. (2) Expressions for the Λ-type splitting in a 2Π state and the spin splitting in a 2Σ state (caused by their mutual interaction via spin-orbit coupling) are derived. These expressions are valid when the rotational intervals are small compared to both the spin-orbit interaction and the 2Π−2Σ energy separation, but do not place any restriction on the relative size of the latter two quantities. (3) Branch intensity expressions are presented which apply to any [Formula: see text] transition in which the [Formula: see text] states are not contaminated (due to uncoupling phenomena) by states having a different value of Ω.

Experimental verification of the need for either jj or intermediate coupling in the 5f states of plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
K. T. Moore ◽  
M. A. Wall ◽  
A. J. Schwartz ◽  
B. W. Chung ◽  
J. G. Tobin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electron Microscope ◽  
Synchrotron Radiation ◽  
Single Phase ◽  
High Spatial Resolution ◽  
Intermediate Coupling ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
X Ray Absorption

ABSTRACTHere, we demonstrate the power of electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) to investigate the electronic structure plutonium. Using EELS, TEM, and synchrotron-radiation-based X-ray absorption spectroscopy (XAS), we provide the first experimental evidence that Russell-Saunders (LS) coupling fails for the 5f states of Pu. These results support the assumption that only the use of jj or intermediate coupling is appropriate for the 5f states of Pu. EELS experiments were performed in a TEM and are coupled with image and diffraction data, therefore, the measurements are completely phase specific. It is shown that EELS in a TEM may be used to circumvent the difficulty of producing single-phase or single-crystal samples due to its high spatial resolution.

scholarly journals Flat-band conditions influenced by spin-orbit interaction in the presence of external magnetic field

2021 ◽  
Vol 11 (5) ◽  
pp. 171-179
Author(s):  
Nóra Kucska ◽  
Zsolt Gulácsi
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Orbit Interaction ◽  
Flat Band ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Many Body ◽  
Spin Orbit Interaction ◽  
Coupling Strengths

We deduct conditions for the Hamiltonian coupling strengths necessary to achieve flat bands in polymers (i.e. a pentagon chain) considering many-body spin-orbit coupling and external magnetic field. We consider itinerant electrons on pentagon chains with first neighbour hoppings, on-site electron potentials and spin-flip first neighbour hoppings representing the Rashba type spin-orbit interaction (SOI). The external magnetic field is also present in the system via the Peierls phase factors. The band structure is obtained by solving the secular equation of the diagonalized one particle part of the Hamiltonian in k-space (momentum-space). The flat band conditions make the bands k-independent, providing a highly a degenerate state, which gives broad possibilities for applications. In our work we have shown how the SOI is able to relax the strict, rigid flat band conditions given by the Hamiltonian coupling strengths. The role of the external magnetic field was also investigated.

ELECTRON TRANSPORT THROUGH A MESOSCOPIC DEVICE WITH THE SPIN-ORBIT COUPLING SEMICONDUCTOR LEADS

2011 ◽  
Vol 25 (12) ◽  
pp. 1671-1680 ◽  
Author(s):  
SHU-GUANG CHENG ◽  
XIAO-JUAN ZHAO ◽  
PEI ZHAO
Keyword(s):  
Electron Transport ◽  
Electronic Transport ◽  
Function Method ◽  
Orbit Interaction ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Rashba Spin ◽  
Non Equilibrium Green’S Function ◽  
Linear Conductance

The electronic transport through a mesoscopic confining region coupled to two spin-orbit coupling semiconductor leads is studied. We mainly focus on how the transport behaviors are affected by the Rashba spin-orbit interaction (SOI), which has been neglected in the previous theoretical papers but indeed exists in the semiconductor leads from the recent experimental results. By using Landauer–Büttiker formula and the non-equilibrium Green's function method, the linear conductance of this device is obtained. The numerical results exhibit that the conductance are similar for the two cases of the absence and the presence of the SOI. It means that the SOI in the leads does not qualitatively affects the transport behaviors. However, in detail, the peaks of the conductance are widened and enhanced by the SOI. In some specific cases, the widening and the enhancement could be very strong.

Spin–orbit splitting in 2Δ states of diatomic molecules

1969 ◽  
Vol 47 (23) ◽  
pp. 2727-2730 ◽  
Author(s):  
H. Lefebvre-Brion ◽  
N. Bessis
Keyword(s):  
Diatomic Molecules ◽  
Orbit Interaction ◽  
Second Order ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Good Agreement

The origin of the splitting of the 2Δ states arising from the σπ2 configuration is studied. For light diatomic molecules, the splitting is shown to arise from the spin–other–orbit interaction which gives a small negative value for the spin–orbit coupling constant A. Non-empirical calculations of A for the 2Δ states of the CH, NH+, and NO molecules are in good agreement with experiment. In heavier molecules, the spin–other–orbit interaction becomes negligible and the second-order spin–orbit effect is dominant.

scholarly journals Ballistic anisotropic magnetoresistance in core–shell nanowires and rolled-up nanotubes

2017 ◽  
Vol 31 (01) ◽  
pp. 1630016 ◽  
Author(s):  
Ching-Hao Chang ◽  
Carmine Ortix
Keyword(s):  
Magnetic Fields ◽  
Orbit Interaction ◽  
Anisotropic Magnetoresistance ◽  
Core Shell ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Ballistic Conductance ◽  
Ferromagnetic Nanostructures ◽  
Semiconducting Nanostructures ◽  
Shell Nanowires

In ferromagnetic nanostructures, the ballistic anisotropic magnetoresistance (BAMR) is a change in the ballistic conductance with the direction of magnetization due to spin–orbit interaction. Very recently, a directional dependent ballistic conductance has been predicted to occur in a number of newly synthesized nonmagnetic semiconducting nanostructures subject to externally applied magnetic fields, without necessitating spin–orbit coupling. In this paper, we review past works on the prediction of this BAMR effect in core–shell nanowires (CSN) and rolled-up nanotubes (RUNTs). This is complemented by new results, we establish for the transport properties of tubular nanosystems subject to external magnetic fields.

scholarly journals Oxidation and aging in U and Pu probed by spin-orbit sum rule analysis: Indications for covalent metal-oxide bonds

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
K. T. Moore ◽  
G. van der Laan ◽  
R. G. Haire ◽  
M. A. Wall ◽  
A. J. Schwartz
Keyword(s):  
Metal Oxide ◽  
Spin Orbit ◽  
Sum Rule ◽  
Rule Analysis

scholarly journals Effects of Rashba Spin-Orbit Coupling On the Anisotropic Magneto Resistance in Domain Wall -=SUP=-*-=/SUP=-

2018 ◽  
Vol 60 (7) ◽  
pp. 1321
Author(s):  
J. Azizi
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
Orbit Interaction ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Electron Current ◽  
Rashba Spin ◽  
Magneto Resistance ◽  
Rashba Coupling ◽  
Classical Boltzmann Equation

AbstractThe present paper, based on semi-classical Boltzmann equation, aims to investigate the effects of Rashba and Dresselhaus spin orbit interaction and impurities on domain wall anisotropic magneto resistance. It has been shown that the mentioned effects play a remarkable role in anisotropic magneto resistance of electron current in domain walls. It was also concluded that while an increase in Rashba coupling strength can effectively enhance anisotropic magneto resistance of the domain wall, an increase in the wave-vector and exchange interaction leads to their decrease.

scholarly journals Structural Quality and Magnetotransport Properties of Epitaxial Layers of the (Ga,Mn)(Bi,As) Dilute Magnetic Semiconductor

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5507
Author(s):  
Tomasz Andrearczyk ◽  
Khrystyna Levchenko ◽  
Janusz Sadowski ◽  
Jaroslaw Z. Domagala ◽  
Anna Kaleta ◽  
...  
Keyword(s):  
Dilute Magnetic Semiconductor ◽  
Magnetic Semiconductor ◽  
Misfit Strain ◽  
Orbit Coupling ◽  
Structural Quality ◽  
Epitaxial Layers ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Transmission Electron ◽  
Strong Spin

Structural analysis of epitaxial layers of the (Ga,Mn)(Bi,As) quaternary dilute magnetic semiconductor (DMS), together with investigations of their magnetotransport properties, has been thoroughly performed. The obtained results are compared with those for the reference (Ga,Mn)As layers, grown under similar conditions, with the aim to reveal an impact of Bi incorporation on the properties of this DMS material. Incorporation of Bi into GaAs strongly enhances the spin-orbit coupling strength in this semiconductor, and the same has been expected for the (Ga,Mn)(Bi,As) alloy. In turn, importantly for specific spintronic applications, strong spin-orbit coupling in ferromagnetic systems opens a possibility of directly controlling the direction of magnetization by the electric current. Our investigations, performed with high-resolution X-ray diffractometry and transmission electron microscopy, demonstrate that the (Ga,Mn)(Bi,As) layers of high structural quality and smooth interfaces can be grown by means of the low-temperature molecular-beam epitaxy method, despite a large difference between the sizes of Bi and As atoms. Depending on the applied buffer layer, the DMS layers can be grown under either compressive or tensile misfit strain, which influences their magnetic properties. It is shown that even small 1% Bi content in the layers strongly affects their magnetoelectric properties, such as the coercive field and anisotropic magnetoresistance.

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