اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدEffect of dilution of both A- and B- sites on the multiferroic properties of spinal Mott insulators
56
0
0.0
(
0
)
تأليف
Prashant Shahi
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The structural, magnetic, electrical and transport properties of FeV2O4, by doping Li and Cr ions respectively in A and B sites, have been studied. Dilution of A-site by Li doping increases the ferri-magnetic ordering temperature and decreases the ferroelectric transition temperature. This also decreases the V-V distances which in effect increases the A-V coupling. This increased A-V coupling dominates over the decrease in A-V coupling due to doping of non-magnetic Li. On the other hand, Cr doping increases the ferri-magnetic ordering temperature but does not alter the ferroelectric transition temperature which is due to the fact that the polarization origin to the presence of almost non-substituted regions.
قيم البحث
اقرأ أيضاً
In the framework of cluster perturbation theory for the 2D Hubbard and Hubbard-Holstein models at low hole doping we have studied the effect of local and short-range correlations in strongly correlated systems on the anomalous features in the electro
nic spectrum by investigating the fine structure of quasiparticle bands. Different anomalous features of spectrum are obtained as the result of intrinsic properties of strongly correlated electron and polaron bands in the presence of short-range correlations. Particularly, features similar to the electron-like Fermi-pockets of cuprates at hole doping $psim0.1$ are obtained without ad hoc introducing a charge density wave order parameter within the Hubbard model in a unified manner with other known peculiarities of the pseudogap phase like Fermi-arcs, pockets, waterfalls, and kink-like features. The Fermi surface is mainly formed by dispersive quasiparticle bands with large spectral weight, formed by coherent low-energy exications. Within the Hubbard-Holstein model at moderate phonon frequencies we show that modest values of local electron-phonon interaction are capable of introducing low-energy kink-like features and affecting the Fermi surface by hybridization of the fermionic quasiparticle bands with the Franck-Condon resonances.
Unravelling the nature of doping-induced transition between a Mott insulator and a weakly correlated metal is crucial to understanding novel emergent phases in strongly correlated materials. For this purpose, we study the evolution of spectral proper
ties upon doping Mott insulating states, by utilizing the cluster perturbation theory on the Hubbard and t-J-like models. Specifically, a quasi-free dispersion crossing the Fermi level develops with small doping, and it eventually evolves into the most dominant feature at high doping levels. Although this dispersion is related to the free electron hopping, our study shows that this spectral feature is in fact influenced inherently by both electron-electron correlation and spin exchange interaction: the correlation destroys coherence, while the coupling between spin and mobile charge restores it in the photoemission spectrum. Due to the persistent impact of correlations and spin physics, the onset of gaps or the high-energy anomaly in the spectral functions can be expected in doped Mott insulators.
We present the results of the magnetic and specific heat measurements on V4 tetrahedral-cluster compound GaV4S8 between 2 to 300K. We find two transitions related to a structural change at 42K followed by ferromagnetic order at 12K on cooling. Remark
ably similar properties were previously reported for the cluster compounds of Mo4. These compounds show an extremely high density of low energy excitations in their electronic properties. We explain this behavior in a cluster compound as due to the reduction of coulomb repulsion among electrons that occupy highly degenerate orbits of different clusters.
We demonstrate that the sign structure of the t-J model on a hypercubic lattice is entirely different from that of a Fermi gas, by inspecting the high temperature expansion of the partition function up to all orders, as well as the multi-hole propaga
tor of the half-filled state and the perturbative expansion of the ground state energy. We show that while the fermion signs can be completely gauged away by a Marshall sign transformation at half-filling, the bulk of the signs can be also gauged away in a doped case, leaving behind a rarified irreducible sign structure that can be enumerated easily by counting exchanges of holes with themselves and spins on their real space paths. Such a sparse sign structure implies a mutual statistics for the quantum states of the doped Mott insulator.
The inverse Faraday effect (IFE), where a static magnetization is induced by circularly polarized light, offers a promising route to ultrafast control of spin states. Here we study the inverse Faraday effect in Mott insulators using the Floquet theor
y. In the Mott insulators with inversion symmetry, we find that the effective magnetic field induced by the IFE couples ferromagnetically to the neighboring spins. While for the Mott insulators without inversion symmetry, the effective magnetic field due to IFE couples antiferromagnetically to the neighboring spins. We apply the theory to the spin-orbit coupled single- and multi-orbital Hubbard model that is relevant for the Kitaev quantum spin liquid materials and demonstrate that the magnetic interactions can be tuned by light.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
