scholarly journals Intrinsic First and Higher-Order Topological Superconductivity in a Doped Topological Insulator

2021 ◽  
Author(s):  
Harley Scammell ◽  
Julian Ingham ◽  
Max Geier ◽  
Tommy Li
Keyword(s):  
Chemical Potential ◽  
Interaction Strength ◽  
Higher Order ◽  
Second Order ◽  
Orbit Coupling ◽  
Order Topology ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Wave State ◽  
Topological Superconductivity

Abstract We explore higher-order topological superconductivity in an artificial Dirac material with intrinsic spin-orbit coupling. A mechanism for superconductivity due to repulsive interactions – pseudospin pairing – has recently been shown to result in higher-order topology in Dirac systems past a minimum chemical potential [1]. Here we apply this theory through microscopic modelling of a superlattice potential imposed on an inversion symmetric hole-doped semiconductor heterostructure, and extend previous work to include the effects of spin-orbit coupling. We find spin-orbit coupling enhances interaction effects, providing an experimental handle to increase the efficiency of the superconducting mechanism. We find that the phase diagram, as a function of chemical potential and interaction strength, contains three superconducting states – a first-order topological p + ip state, a second-order topological spatially modulated p + iτp state, and a second-order topological extended s-wave state, sτ. We calculate the symmetry-based indicators for the p + iτp and sτ states, which prove these states possess second-order topology. Exact diagonalisation results are presented which illustrate the interplay between the boundary physics and spin orbit interaction. We argue that this class of systems offer an experimental platform to engineer and explore first and higher-order topological superconducting states.

A theoretical study of the 14N and 17O N.M.R. shifts in lanthanide complexes

1972 ◽  
Vol 25 (12) ◽  
pp. 2577 ◽  
Author(s):  
RM Golding ◽  
MP Halton
Keyword(s):  
Hyperfine Interaction ◽  
Lanthanide Complexes ◽  
Theoretical Study ◽  
Second Order ◽  
Orbit Coupling ◽  
Order Perturbation ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Lanthanide Ion ◽  
Isotropic Hyperfine Interaction

The experimental 14N and 17O n.m.r, results in a series of lanthanide complexes are successfully interpreted from a second-order perturbation treatment of the calculation of (S2), where bonding effects and spin-orbit coupling mixing are incorporated. The isotropic hyperfine interaction constants are shown to be negative for 14N and positive for 17O but both independent of the particular lanthanide ion. We also confirm that the 4f orbitals are not involved in direct bonding with the ligands.

scholarly journals Spin Structure Factors of Doped Monolayer Germanene in the Presence of Spin-Orbit Coupling

2021 ◽  
Author(s):  
hamed rezania ◽  
farshad azizi
Keyword(s):  
Magnetic Field ◽  
Spin Structure ◽  
Chemical Potential ◽  
Linear Response Theory ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Structure Factors ◽  
Static Spin ◽  
Dynamical Spin

Abstract In this paper, we present a Kane-Mele model in the presence of magnetic field and next nearest neighbors hopping amplitudes for investigations of the spin susceptibilities of Germanene layer.Green's function approach has been implemented to find the behavior of dynamical spin susceptibilities of Germanene layer within linear response theory and in the presence of magnetic field and spin-orbit coupling at finite temperature.Our results show the magnetic excitation mode for both longitudinal and transverse components of spin tends to higher frequencies with spin-orbit coupling strength.Moreover the frequency positions of sharp peaks in longitudinal dynamical spin susceptibility are not affected by variation of magnetic field while the peaks in transverse dynamical susceptibility moves to lower frequencies with magnetic field.The effects of electron doping on frequency behaviors of spin susceptibilities have been addressed in details.Finally the temperature dependence of static spin structure factors due to the effects of spin-orbit coupling, magnetic field and chemical potential has been studied.

scholarly journals Spin-Orbit Coupling Effect on the Electrophilicity Index, Chemical Potential, Hardness and Softness of Neutral Gold Clusters: A Relativistic Ab-initio Study

2021 ◽  
Vol 2 (1) ◽  
pp. 38-50
Author(s):  
Mahnaz Jabbarzadeh Sani
Keyword(s):  
Chemical Potential ◽  
Coupling Effect ◽  
Gold Clusters ◽  
Orbit Coupling ◽  
Basis Set ◽  
Structure Stability ◽  
Chemical Hardness ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Electrophilicity Index

Electrophilicity index (𝜔) is related to the energy lowering associated with a maximum amount of electron flow between a donor and an acceptor and possesses adequate information regarding structure, stability, reactivity and interactions. Chemical potential (μ) measures charge transfer from a system to another having a lower value of μ, while chemical hardness (η) is a measure of characterizing relative stability of clusters. The main purpose of the present research work is to examine the Spin-Orbit Coupling (SOC) effect on the behavior of the electrophilicity index, chemical potential, hardness and softness of neutral gold clusters Aun (n=2-6). Using the second-order Douglas-Kroll-Hess Hamiltonian, geometries are optimized at the DKH2-B3P86/DZP-DKH level of theory. Spin-orbit coupling energies are computed using the fourth-order Douglas-Kroll-Hess Hamiltonian, generalized Hartree-Fock method and all-electron relativistic double-ζ level basis set. Then, spin-orbit coupling (SOC) corrections to the electrophilicity index, chemical potential, hardness and softness are calculated. It is revealed that spin-orbit correction to the vertical chemical hardness has important effect on Au3 and Au6, i.e. SOC decreases (increases) the hardness of gold trimer (hexamer). Due to the relationship between hardness and softness, σ = , inclusion of spin-orbit coupling increases (decreases) the softness of Au3 (Au6) and thus destabilizes (stabilizes) it. Spin-orbit coupling (SOC) also has more important effect on the chemical potential of Au3 by decreasing its value. It is found that spin-orbit coupling has considerable effect on the electrophilicity index of gold trimer and greatly increases its value. Furthermore, SOC increases the maximal charge acceptance of Au3 more and thus destabilizes it more. As a result, spin-orbit coupling effect appears to be important in calculating the electrophilicity index of the gold trimer. Doi: 10.28991/HIJ-2021-02-01-05 Full Text: PDF

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.

Sign in / Sign up

Export Citation Format

Share Document