اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدElectric field control of valence tautomeric interconversion in Cobalt dioxolene
172
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We demonstrate that the critical temperature for valence tautomeric interconversion in Cobalt dioxolene complexes can be significantly changed when a static electric field is applied to the molecule. This is achieved by effectively manipulating the redox potential of the metallic acceptor forming the molecule. Importantly our accurate density functional theory calculations demonstrate that already a field of 0.1 V/nm, achievable in Stark spectroscopy experiments, can produce a change in the critical temperature for the interconversion of 20 K. Our results indicate a new way for switching on and off the magnetism in a magnetic molecule. This offers the unique chance of controlling magnetism at the atomic scale by electrical means.
قيم البحث
اقرأ أيضاً
We present an ab initio molecular dynamics (MD) investigation of the tautomeric equilibrium for aqueous solutions of glycine and acetone at realistic experimental conditions. Metadynamics is used to accelerate proton migration among tautomeric center
s. Due to the formation of complex water-ion structures involved the proton dynamics in the aqueous environment, standard enhanced sampling approaches may face severe limitations in providing a general description of the phenomenon. Recently, we developed a set of Collective Variables (CVs) designed to study protons transfer reactions in complex condensed systems [Grifoni et al. PNAS, 2019, 116(10), 4054-4057]. In this work we applied this approach to study proton dissociation dynamics leading to tautomeric interconversion of biologically and chemically relevant prototypical systems, namely glycine and acetone in water. Although relatively simple from a chemical point of view, the results show that even for these small systems complex reaction pathways and non-trivial conversion dynamics are observed. The generality of our method allows obtaining these results without providing any prior information on the dissociation dynamics but only the atomic species that can exchange protons in the process. Our results agree with literature estimates and demonstrate the general applicability of this method in the study of tautomeric reactions.
The Curie temperature is one of the most fundamental physical properties of ferromagnetic materials and can be described by Weiss molecular field theory with the exchange interaction of neighboring atoms. Recently, the electric-field-induced modulati
on of the Curie temperature has been demonstrated in transition metals. This can be interpreted as indirect evidence for the electrical modulation of exchange coupling. However, the scenario has not yet been experimentally verified. Here, we demonstrate the electrical control of exchange coupling in cobalt film from direct magnetization measurements. We find that the reduction in magnetization with temperature, which is caused by thermal spin wave excitation and scales with Blochs law, clearly depends on the applied electric field. Furthermore, we confirm that the correlation between the electric-field-induced modulation of the Curie temperature and that of exchange coupling follows Weiss molecular field theory.
We propose and analyze a novel flopping-mode mechanism for electric dipole spin resonance based on the delocalization of a single electron across a double quantum dot confinement potential. Delocalization of the charge maximizes the electronic dipole
moment compared to the conventional single dot spin resonance configuration. We present a theoretical investigation of the flopping-mode spin qubit properties through the crossover from the double to the single dot configuration by calculating effective spin Rabi frequencies and single-qubit gate fidelities. The flopping-mode regime optimizes the artificial spin-orbit effect generated by an external micromagnet and draws on the existence of an externally controllable sweet spot, where the coupling of the qubit to charge noise is highly suppressed. We further analyze the sweet spot behavior in the presence of a longitudinal magnetic field gradient, which gives rise to a second order sweet spot with reduced sensitivity to charge fluctuations.
The spin-orbit coupling (SOC) can mediate electric-dipole spin resonance (EDSR) in an a.c. electric field. In this letter, the EDSR is essentially understood as an spin precession under an effective a.c. magnetic field induced by the SOC in the refer
ence frame, which is exactly following the classical trajectory of the electron and obtained by applying a quantum linear coordinate transformation. With this observation for one-dimensional (1D) case, we find a upper limit for the spin-flipping speed in the EDSR-based control of spin, which is given by the accessible data from the current experiment. For two-dimensional case, the azimuthal dependence of the effective magnetic field can be used to measure the ratio of the Rashba and Dresselhause SOC strengths.
The polar covalent bond between a single Au atom terminating the apex of an atomic force microscope tip and a C atom of graphene on SiC(0001) is exposed to an external electric field. For one field orientation the Au-C bond is strong enough to sustai
n the mechanical load of partially detached graphene, whilst for the opposite orientation the bond breaks easily. Calculations based on density functional theory and nonequilibrium Greens function methods support the experimental observations by unveiling bond forces that reflect the polar character of the bond. Field-induced charge transfer between the atomic orbitals modifies the polarity of the different electronegative reaction partners and the Au-C bond strength.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
