scholarly journals Spin-orbit Hamiltonian for organic crystals from first-principles electronic structure and Wannier functions

2017 ◽  
Vol 95 (8) ◽  
Author(s):  
Subhayan Roychoudhury ◽  
Stefano Sanvito
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Organic Crystals ◽  
Spin Orbit ◽  
Wannier Functions

scholarly journals The Influence of Electronic Structure Modelling and Junction Structure on First-Principles Chiral Induced Spin Selectivity

2020 ◽  
Author(s):  
Martin Sebastian Zöllner ◽  
Vladimiro Mujica ◽  
Carmen Herrmann
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Orbit Coupling ◽  
First Principles Calculation ◽  
Physical Parameters ◽  
Theory Approach ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Junction Structure

<br>We have carried out a comprehensive study of the influence of electronic structure modeling and junction structure description on the first-principles calculation of the spin polarization in molecular junctions caused by the chiral induced spin selectivity (CISS) effect. We explore the limits and the sensitivity to modelling decisions of a Landauer / Green’s function / density functional theory approach to CISS. We find that although the CISS effect is entirely attributed in the literature to molecular spin filtering, spin-orbit coupling being partially inherited from the metal electrodes plays an important role in our calculations, even though this effect cannot explain the experi- mental conductance results. Also, an important dependence on the specific description of exchange interaction and spin–orbit coupling is manifest in our approach. This is important because the interplay between exchange effects and spin-orbit coupling may play an important role in the description of the junction magnetic response. Our calculations are relevant for the whole field of spin-polarized electron transport and electron transfer because there is still an open discussion in the literature about the detailed underlying mechanism and the magnitude of relevant physical parameters that need to be included to achieve a consistent description of the CISS effect<br>

Electronic structure and transport properties of ternary skutterudite: CoX3/2Y3/2

2009 ◽  
Vol 1166 ◽  
Author(s):  
Dmitri Volja ◽  
Marco Fornari ◽  
Boris Kozinsky ◽  
Nicola Marzari
Keyword(s):  
Electronic Structure ◽  
Transport Properties ◽  
Valence Band ◽  
Power Factor ◽  
First Principles ◽  
First Principles Calculations ◽  
Wannier Functions ◽  
Effective Masses ◽  
Fundamental Cause ◽  
Parabolic Dispersion

AbstractElectronic properties of ternary skutterudites AX3/2Y3/2 (A=Co, X=Ge, Sn and Y=S, Te) are investigated using first principles calculations to clarify recent experimental results. Band derivatives are computed accurately within an approach based on Maximally Localized Wannier Functions (MLWFs). Band structures exhibit larger effective masses compared to parental binary CoSb3. Our results also indicate a more parabolic dispersion near the top of the valence band and a multivalley character in both conduction and valence band. Despite the improved thermopower these skutterudites has relatively low power factor due to increased resistivity. The fundamental cause of such large resistivity seems to be associated with the ionicity of the bonding.

The electronic structure and spin–orbit-induced spin splitting in antimonene with vacancy defects

RSC Advances ◽  
2016 ◽  
Vol 6 (70) ◽  
pp. 66140-66146 ◽  
Author(s):  
Lifang Yang ◽  
Yan Song ◽  
Wenbo Mi ◽  
Xiaocha Wang
Keyword(s):  
Electronic Structure ◽  
Electronic Properties ◽  
First Principles ◽  
Spin Splitting ◽  
Spin Orbit ◽  
First Principles Calculations ◽  
Vacancy Defects

We study the geometric, electronic properties, and spin splitting in monovacancy (MV) and divacancy (DV) antimonene with five different models using first-principles calculations.

scholarly journals Electronic structure of biaxially strained wurtzite crystals GaN, AlN, and InN

1996 ◽  
Vol 1 ◽  
Author(s):  
J. A. Majewski ◽  
M. Städele ◽  
P. Vogl
Keyword(s):  
Electronic Structure ◽  
Total Energy ◽  
Valence Band ◽  
First Principles ◽  
Degrees Of Freedom ◽  
Local Density ◽  
Structural Parameters ◽  
Spin Orbit ◽  
Biaxial Strain ◽  
Valence Band State

We present first-principles studies of the effect of biaxial (0001)-strain on the electronic structure of wurtzite GaN, AlN, and InN. We provide accurate predictions for the valence band splittings as a function of strain which greatly facilitates the interpretation of data from samples with unintentional growth-induced strain. The present calculations are based on the total-energy pseudopotential method within the local-density formalism and include the spin-orbit interaction nonperturbatively. For a given biaxial strain, all structural parameters are determined by minimization of the total energy with respect to the electronic and ionic degrees of freedom. Our calculations predict that the valence band state Γ9(Γ6) lies energetically above the Γ7(Γ1) states in GaN and InN, in contrast to the situation in AlN. In all three nitrides, we find that the ordering of these two levels becomes reversed for some value of biaxial strain. In GaN, this crossing takes place already at 0.32% tensile strain. For larger tensile strains, the top of the valence band becomes well separated from the lower states. The computed crystal-field and spin-orbit splittings in unstrained materials as well as the computed deformation potentials agree well with the available experimental data.

The Influence of Electronic Structure Modelling and Junction Structure on First-Principles Chiral Induced Spin Selectivity

2020 ◽  
Author(s):  
Martin Sebastian Zöllner ◽  
Vladimiro Mujica ◽  
Carmen Herrmann
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Orbit Coupling ◽  
First Principles Calculation ◽  
Physical Parameters ◽  
Theory Approach ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Junction Structure

<br>We have carried out a comprehensive study of the influence of electronic structure modeling and junction structure description on the first-principles calculation of the spin polarization in molecular junctions caused by the chiral induced spin selectivity (CISS) effect. We explore the limits and the sensitivity to modelling decisions of a Landauer / Green’s function / density functional theory approach to CISS. We find that although the CISS effect is entirely attributed in the literature to molecular spin filtering, spin-orbit coupling being partially inherited from the metal electrodes plays an important role in our calculations, even though this effect cannot explain the experi- mental conductance results. Also, an important dependence on the specific description of exchange interaction and spin–orbit coupling is manifest in our approach. This is important because the interplay between exchange effects and spin-orbit coupling may play an important role in the description of the junction magnetic response. Our calculations are relevant for the whole field of spin-polarized electron transport and electron transfer because there is still an open discussion in the literature about the detailed underlying mechanism and the magnitude of relevant physical parameters that need to be included to achieve a consistent description of the CISS effect<br>

Electronic Structure of Biaxially-Strained Wurtzite Crystals GaN and AlN

1996 ◽  
Vol 449 ◽  
Author(s):  
J. A. Majewski ◽  
M. Städele ◽  
P. Vogl
Keyword(s):  
Experimental Data ◽  
Electronic Structure ◽  
Effective Mass ◽  
Valence Band ◽  
Crystal Field ◽  
First Principles ◽  
Local Density ◽  
Pseudopotential Method ◽  
Spin Orbit ◽  
Spin Orbit Interactions

ABSTRACTWe present first-principles studies of the effect of biaxial (OOOl)-strain on the electronic structure of wurtzite GaN, and A1N. We provide accurate predictions of the valence band splittings as a function of strain, which may facilitate the interpretation of data from strained samples. The conduction and valence band effective mass tensors for A1N and GaN are also presented. The computed crystal-field and spin-orbit splittings in unstrained materials as well as the computed deformation potentials are in accord with available experimental data. We show that the numerically computed band energies can be excellently represented in terms of a 6-band k · p model. The present calculations are based on the first-principles pseudopotential method within the local-density formalism and include the spin-orbit interactions non-perturbatively.

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