scholarly journals Energy levels of a two-dimensional hydrogen atom with spin-orbit Rashba interaction

2008 ◽  
Vol 77 (11) ◽  
Author(s):  
C. Grimaldi
Keyword(s):  
Hydrogen Atom ◽  
Energy Levels ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Rashba Interaction

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>

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>

scholarly journals Exact Noncommutative Two-Dimensional Hydrogen Atom

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
B. C. Wang ◽  
E. C. Brenag ◽  
R. G. G. Amorim ◽  
V. C. Rispoli ◽  
S. C. Ulhoa
Keyword(s):  
Experimental Data ◽  
Hydrogen Atom ◽  
Schrödinger Equation ◽  
Coulomb Potential ◽  
Schrodinger Equation ◽  
Energy Levels ◽  
Two Dimensional ◽  
Exact Analysis

In this work, we present an exact analysis of the two-dimensional noncommutative hydrogen atom. In this study, the Levi-Civita transformation was used to perform the solution of the noncommutative Schrodinger equation for Coulomb potential. As an important result, we determine the energy levels for the considered system. Using the result obtained and experimental data, a bound on the noncommutativity parameter was obtained.

scholarly journals The influence of Coulomb interaction screening on the excitons in disordered two-dimensional insulators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. V. Kirichenko ◽  
V. A. Stephanovich
Keyword(s):  
Coulomb Interaction ◽  
Energy Levels ◽  
Transition Metal Dichalcogenides ◽  
Extreme Case ◽  
Bound State ◽  
Joint Effect ◽  
Two Dimensional ◽  
Inorganic Substances ◽  
Metal Dichalcogenides ◽  
Interaction Screening

AbstractWe study the joint effect of disorder and Coulomb interaction screening on the exciton spectra in two-dimensional (2D) structures. These can be van der Waals structures or heterostructures of organic (polymeric) semiconductors as well as inorganic substances like transition metal dichalcogenides. We consider 2D screened hydrogenic problem with Rytova–Keldysh interaction by means of so-called fractional Scrödinger equation. Our main finding is that above synergy between screening and disorder either destroys the exciton (strong screening) or promote the creation of a bound state, leading to its collapse in the extreme case. Our second finding is energy levels crossing, i.e. the degeneracy (with respect to index $$\mu $$ μ ) of the exciton eigenenergies at certain discrete value of screening radius. Latter effects may also be related to the quantum manifestations of chaotic exciton behavior in above 2D semiconductor structures. Hence, they should be considered in device applications, where the interplay between dielectric screening and disorder is important.

Ground configuration splitting in UCl5

1977 ◽  
Vol 55 (10) ◽  
pp. 937-942 ◽  
Author(s):  
A. F. Leung ◽  
Ying-Ming Poon
Keyword(s):  
Crystal Field ◽  
Energy Levels ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Point Charge Model ◽  
X Ray Crystallography ◽  
Charge Model ◽  
Crystal Field Parameters

The absorption spectra of UCl5 single crystal were observed in the region between 0.6 and 2.4 μm at room, 77, and 4.2 K temperatures. Five pure electronic transitions were assigned at 11 665, 9772, 8950, 6643, and 4300 cm−1. The energy levels associated with these transitions were identified as the splittings of the 5f1 ground configuration under the influence of the spin–orbit coupling and a crystal field of C2v symmetry. The number of crystal field parameters was reduced by assuming the point-charge model where the positions of the ions were determined by X-ray crystallography. Then, the crystal field parameters and the spin–orbit coupling constant were calculated to be [Formula: see text],[Formula: see text], [Formula: see text], and ξ = 1760 cm−1. The vibronic analysis showed that the 90, 200, and 320 cm−1 modes were similar to the T2u(v6), T1u(v4), and T1u(v3) of an UCl6− octahedron, respectively.

scholarly journals NONCOMMUTATIVE GRAPHENE

2013 ◽  
Vol 28 (16) ◽  
pp. 1350064 ◽  
Author(s):  
CATARINA BASTOS ◽  
ORFEU BERTOLAMI ◽  
NUNO COSTA DIAS ◽  
JOÃO NUNO PRATA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Dirac Equation ◽  
Energy Levels ◽  
Dirac Fermions ◽  
Two Dimensional ◽  
Dirac System ◽  
Noncommutative Parameter

We consider a noncommutative description of graphene. This description consists of a Dirac equation for massless Dirac fermions plus noncommutative corrections, which are treated in the presence of an external magnetic field. We argue that, being a two-dimensional Dirac system, graphene is particularly interesting to test noncommutativity. We find that momentum noncommutativity affects the energy levels of graphene and we obtain a bound for the momentum noncommutative parameter.

scholarly journals Exotic spin phases in two-dimensional spin-orbit coupled models: Importance of quantum effects

2017 ◽  
Vol 96 (11) ◽  
Author(s):  
Chao Wang ◽  
Ming Gong ◽  
Yongjian Han ◽  
Guangcan Guo ◽  
Lixin He
Keyword(s):  
Quantum Effects ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Coupled Models
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