0000000001303188
AUTHOR
Sergey M. Aldoshin
Can the Double Exchange Cause Antiferromagnetic Spin Alignment?
The effect of the double exchange in a square-planar mixed-valence dn+1&minus
Insight Into The Spin-Vibronic Problem of a Mixed Valence Magnetic Molecular Cell for Quantum Cellular Automata.
The effects of the vibronic coupling in quantum cellular automata (QCA) based on the square planar mixed valence (MV) molecular cells comprising four paramagnetic centers (spin cores) and two excess mobile electrons are analyzed in the important particular case when the Coulomb energy gap between the ground antipodal diagonal-type two-electron configurations and the excited side-type configurations considerably exceeds both the one-electron transfer parameter (strong U-limit) and the vibronic stabilization energy. Under such conditions the developed model involves the second-order double exchange, the Heisenberg-Dirac-Van Vleck (HDVV) exchange and the vibronic coupling of the excess electro…
Purely Spectroscopic Determination of the Spin Hamiltonian Parameters in High-Spin Six-Coordinated Cobalt(II) Complexes with Large Zero-Field Splitting.
Accurate determination of the spin Hamiltonian parameters in transition-metal complexes with large zero-field splitting (ZFS) is an actual challenge in studying magnetic and spectroscopic properties of high-spin transition metal complexes. Recent critical papers have convincingly shown that previous determinations of these parameters, based only on the magnetic data, have low accuracy and reliability. A combination of X-band electron paramagnetic resonance (EPR) spectroscopy and SQUID magnetometry seems to be a more convincing and accurate approach. However, even in this case, the accuracy of the determination of the spin Hamiltonian parameters is strongly limited. In this work, we propose …
Electric Field Control of Spin States in Trigonal Two-Electron Quantum Dot Arrays and Mixed-Valence Molecules: II. Vibronic Problem
In this article, the vibronic model for an electric field switchable mixed-valence trimer containing two delocalized electrons or holes is proposed and examined. The role of the vibronic coupling on the electric field effects is analyzed by means of the semiclassical adiabatic approach and, alternatively, with the aid of the numerical analysis of the Schrodinger equation with due allowance for the kinetic energy of the ions (dynamic problem). The adiabatic potential landscapes have been calculated by taking into account the influence of the electric field. As the adiabatic approximation has a limited frame of validity, the study of the electric field effects has also been performed within m…
Localization–Delocalization in Bridged Mixed-Valence Metal Clusters: Vibronic PKS Model Revisited
Here we describe a new vibronic model of mixed valence (MV) dimer inspired by the conventional Piepho, Krausz, and Schatz (PKS) approach. We attempted to partially lift the main restriction of the PKS model dealing with the vibronically independent moieties of a MV molecule. The refined version of the PKS model in which the bridging ligands are included deals with the three main interactions: electron transfer (integral t0) related to the high-symmetric ligand configuration, on-site vibronic coupling (parameter υ) arising from the modulation of the crystal field on the metal sites by the breathing displacements of their nearest ligand surroundings, and intercenter vibronic coupling (paramet…
Mixed-Valence Magnetic Molecular Cell for Quantum Cellular Automata: Prospects of Designing Multifunctional Devices through Exploration of Double Exchange
In this article, we propose to use multielectron square-planar mixed-valence (MV) molecules as molecular cells for quantum cellular automata (QCA) devices. As distinguished from previous proposals ...
Electrically switchable magnetic exchange in the vibronic model of linear mixed valence triferrocenium complex
In this article, we report our development of a vibronic model for the electric-field control of antiferromagnetic superexchange in the mixed-valence (MV) triferrocenium complex FeIII-FeII-FeIII proposed as a possible candidate for the molecular implementation of a quantum logic gate. Along with the electronic interactions, such as electron transfer between the iron ions in different oxidation degrees and Coulomb repulsion of the extra holes, the proposed model of the triferrocenium complex also takes into account the vibronic coupling as an inherent ingredient of the problem of mixed valency. The latter is described by the conventional Piepho-Krauzs-Shatz (PKS) model adapted to the linear …
Electric field controllable magnetic coupling of localized spins mediated by itinerant electrons: a toy model
In this paper, we propose a toy model to describe the magnetic coupling between the localized spins mediated by the itinerant electron in partially delocalized mixed-valence (MV) systems. This minimal model takes into account the key interactions that are common for all such systems, namely, electron transfer in the valence-delocalized moiety and magnetic exchange between the localized spins and the delocalized electrons. The proposed descriptive model is exactly solvable which allows us to qualitatively and quantitatively discuss the main features of the whole class of partially delocalized MV systems. In the case of relatively strong exchange coupling, the combined action of these two int…
Vibronic Model for Intercommunication of Localized Spins via Itinerant Electron
In this article, we propose a vibronic pseudo Jahn–Teller model for partially delocalized mixed-valence molecules aimed to describe the magnetic coupling between the localized spins mediated by the delocalized electron. The simplest partially delocalized system that retains the main studied features is assumed to consist of a one-electron mixed-valence dimer, which is connected to the two terminal magnetic ions. The model involves the following key interactions: electron transfer in the spin-delocalized subsystem of a mixed-valence molecule, which is mimicked by a dimeric unit, coupling of the itinerant electrons with the molecular vibrations, and isotropic magnetic exchange between the loc…
Toward multifunctional molecular cells for quantum cellular automata: exploitation of interconnected charge and spin degrees of freedom
We discuss the possibility of using mixed-valence (MV) dimers comprising paramagnetic metal ions as molecular cells for quantum cellular automata (QCA). Thus, we propose to combine the underlying idea behind the functionality of QCA of using the charge distributions to encode binary information with the additional functional options provided by the spin degrees of freedom. The multifunctional ('smart') cell is supposed to consist of multielectron MV d(n)-d(n+1)-type (1 ≤ n ≤ 8) dimers of transition metal ions as building blocks for composing bi-dimeric square planar cells for QCA. The theoretical model of such a cell involves the double exchange (DE), Heisenberg-Dirac-Van Vleck (HDVV) excha…
Exploration of the double exchange in quantum cellular automata: proposal for a new class of cells
In this communication we propose to considerably extend the class of systems suitable as cells for quantum cellular automata by including magnetic quantum dots and molecular mixed valence dimers exhibiting double exchange. As distinguished from the previous works we propose to use not only charges as the information carriers but also spin degrees of freedom. In this context we focus on the two key points: (1) properties of the magnetic cell as reservoir for charges carrying binary information, and (2) identification of conditions under which spin degrees of freedom can be employed.
Electric Field Generation and Control of Bipartite Quantum Entanglement between Electronic Spins in Mixed Valence Polyoxovanadate [GeV14O40]8–
As part of the search for systems in which control of quantum entanglement can be achieved, here we consider the paramagnetic mixed valence polyoxometalate K2Na6[GeV14O40]·10H2O in which two electrons are delocalized over the 14 vanadium ions. Applying a homogeneous electric field can induce an antiferromagnetic coupling between the two delocalized electronic spins that behave independently in the absence of the field. On the basis of the proposed theoretical model, we show that the external field can be used to generate controllable quantum entanglement between the two electronic spins traveling over a vanadium network of mixed valence polyoxoanion [GeV14O40]8–. Within a simplified two-lev…
CCDC 1911055: Experimental Crystal Structure Determination
Related Article: Eugenii Ya. Misochko, Alexander V. Akimov, Denis V. Korchagin, Joscha Nehrkorn, Mykhaylo Ozerov, Andrew V. Palii, Juan Modesto Clemente-Juan, Sergey M. Aldoshin|2019|Inorg.Chem.|58|16434|doi:10.1021/acs.inorgchem.9b02195