EL2 and the Electronic Structure of the AsGa—Asi Pair in GaAs: the Role of Jahn-Teller Relaxation

1987 ◽  
Vol 104 ◽  
Author(s):  
G. A. Baraff ◽  
M. Lannoo ◽  
M. Schluter
Keyword(s):  
Electronic Structure ◽  
Energy Functional ◽  
Excitation Energies ◽  
Defect Pair ◽  
Weakly Interacting ◽  
Jahn Teller

ABSTRACTThe levels and excitation energies of the weakly interacting AsGa—Asi defect pair have been calculated using the model energy functional introduced by Baraff and Schluter, modified so as to allow Jahn Teller relaxation to distort the Asi away from the symmetry site. The physics underlying this calculation and the results emerging from it are described in this paper. We find that many previously unrelated experimental observations about EL2 are well accounted for by this model. However, there are still some controversial aspects of the fit of the model to the observed properties of EL2 which we cite as requiring further study.

scholarly journals Origin of Perovskite Multiferroicity and Magnetoelectric-Multiferroic Effects—The Role of Electronic Spin in Spontaneous Polarization of Crystals

2022 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Isaac B. Bersuker
Keyword(s):  
Electronic Structure ◽  
Spontaneous Polarization ◽  
Magnetic Moments ◽  
Cooperative Interaction ◽  
Opposite Parity ◽  
Multiferroic Properties ◽  
Electronic Spin ◽  
Jahn Teller ◽  
Electric Effects

In this semi-review paper, we show that the multiferroic properties of perovskite ABO3 crystals with B(dn), n > 0, centers are fully controlled by the influence of the electronic spin on the local dipolar instability that triggers the spontaneous polarization of the crystal. Contrary to the widespread statements, the multiferroicity of these crystals does not emerge due to the addition of unpaired electrons (carrying magnetic moments) to the spontaneously polarizing crystal; the spin states themselves are an important part of the local electronic structure that determines the very possibility of the spontaneous polarization. This conclusion emerges from vibronic theory, in which the ferroelectricity is due to the cooperative interaction of the local dipolar distortions induced by the pseudo-Jahn-Teller effect (PJTE). The latter requires sufficiently strong vibronic coupling between ground and excited electronic states with opposite parity but the same spin multiplicity. The detailed electronic structure of the octahedral [B(dn)O6] center in the molecular orbital presentation shows how this requirement plays into the dependence of the possible perovskite magnetic, ferroelectric, and multiferroic properties on the number of d electrons, provided the criterion of the PJTE is obeyed. Revealed in detail, the role of the electronic spin in all these properties and their combination opens novel possibilities for their manipulation by means of external perturbations and exploration. In particular, it is shown that by employing the well-known spin-crossover phenomenon, a series of novel effects become possible, including magnetic-ferroelectric (multiferroic) crossover with electric-multiferroic, magnetic-ferroelectric, and magneto-electric effects, some of which have already been observed experimentally.

Unveiling the role of Mn-interstitial defect and particle size on the Jahn-Teller distortion of the LiMn2O4 cathode material

2021 ◽  
Vol 490 ◽  
pp. 229519
Author(s):  
Renier Arabolla Rodríguez ◽  
Nelcy Della Santina Mohallem ◽  
Manuel Avila Santos ◽  
Demetrio A. Sena Costa ◽  
Luciano Andrey Montoro ◽  
...  
Keyword(s):  
Particle Size ◽  
Cathode Material ◽  
Teller Distortion ◽  
Interstitial Defect ◽  
Jahn Teller ◽  
Limn2o4 Cathode ◽  
Jahn Teller Distortion

scholarly journals Band alignment of monolayer CaP3, CaAs3, BaAs3 and the role of p–d orbital interactions in the formation of conduction band minima

2021 ◽  
Vol 23 (12) ◽  
pp. 7418-7425
Author(s):  
Magdalena Laurien ◽  
Himanshu Saini ◽  
Oleg Rubel
Keyword(s):  
Electronic Structure ◽  
Conduction Band ◽  
Electron Affinity ◽  
Band Alignment ◽  
Orbital Interactions

We calculate the band alignment of the newly predicted phosphorene-like puckered monolayers with G0W0 according to the electron affinity rule and examine trends in the electronic structure. Our results give guidance for heterojunction design.

Site-projected electronic structure of two-dimensional Ti3C2MXene: the role of the surface functionalization groups

2016 ◽  
Vol 18 (45) ◽  
pp. 30946-30953 ◽  
Author(s):  
Damien Magne ◽  
Vincent Mauchamp ◽  
Stéphane Célérier ◽  
Patrick Chartier ◽  
Thierry Cabioc'h
Keyword(s):  
Electronic Structure ◽  
Surface Functionalization ◽  
Chemical Bonding ◽  
Surface Groups ◽  
Two Dimensional ◽  
Object Level

The role of the surface groups in chemical bonding in two dimensional Ti3C2is evidenced at the nano-object level.

scholarly journals Stoichiometry and disorder influence over electronic structure in nanostructured VOx films

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
A. D’Elia ◽  
S. J. Rezvani ◽  
N. Zema ◽  
F. Zuccaro ◽  
M. Fanetti ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Distorted Octahedral Geometry ◽  
Edge Structure ◽  
Distorted Octahedral ◽  
X Ray Absorption ◽  
Complex Matter ◽  
Nanometric Size

AbstractWe present and discuss the role of nanoparticles size and stoichiometry over the local atomic environment of nanostructured VOx films. The samples have been characterized in situ using X-ray absorption near-edge structure (XANES) spectroscopy identifying the stoichiometry-dependent fingerprints of disordered atomic arrangement. In vanadium oxides, the ligand atoms arrange according to a distorted octahedral geometry depending on the oxidation state, e.g. trigonal distortion in V2O3 and tetragonal distortion in bulk VO2. We demonstrate, taking VO2 as a case study, that as a consequence of the nanometric size of the nanoparticles, the original ligands symmetry of the bulk is broken resulting in the coexistence of a continuum of distorted atomic conformations. The resulting modulation of the electronic structure of the nanostructured VOx as a function of the oxygen content reveals a stoichiometry-dependent increase of disorder in the ligands matrix. This work shows the possibility to produce VOx nanostructured films accessing new disordered phases and provides a unique tool to investigate the complex matter.

Sign in / Sign up

Export Citation Format

Share Document