Employing a large-N scheme of the layered t-J model with long-range Coulomb interaction, which captures fine details charge excitation spectra recently observed in cuprate superconductors, we explore role fluctuations on electron self-energy. We fix temperature at zero and focus quantum fluctuations. find pronounced asymmetry imaginary part self-energy Im$\Sigma({\bf k}, \omega)$ respect to $\o...

We investigate the stability of the charge exchange (CE) phase within a microscopic model which describes a single plane as in La0.5Sr1.5MnO4. The model includes Coulomb interactions (on-site and intersite), the Jahn-Teller term and the superexchange interactions due to eg and t2g electrons. By investigating the phase diagram at T = 0 in mean-field approximation we conclude that the superexchan...

We discuss some generalities about the spin gap in cuprate superconductors and in detail, how it arises from the interlayer picture. It can be thought of as spinon (uncharged) pairing, which occurs independently at each point of the 2D Fermi surface because of the momentum selection rule on interlayer superexchange and pair tunneling interactions. Some predictions can be made.

The mechanism of electron transfer in α-aminoisobutyric (Aib) homoligomers is defined by the extent of secondary structure, rather than just chain length. Helical structures (Aib units ≥3) undergo an electron hopping mechanism, while shorter disordered sequences (Aib units <3) undergo an electron superexchange mechanism.

We point out that both superexchange between CuO2 layers, and interlayer tunneling, derive from frustrated one-particle hopping between layers, and that they should be treated on an equal footing. Doing so, we arrive at a new view of the nature of pairing in the cuprate supercondcutors, which explains the striking even ↔ odd selection rule observed by Keimer in neutron scattering by YBCO.

We simulate the effects of two types of dephasing processes, a nonlocal dephasing of system eigenstates and a dephasing of semilocal eigenstates, on the rate and mechanism of electron transfer (eT) through a series of donor-bridge-acceptor systems, D-B(N)-A, where N is the number of identical bridge units. Our analytical and numerical results show that pure dephasing, defined as the perturbatio...

Mn2Ge2Te6 shows intrinsic ferromagnetic (FM) order, with a Curie temperature (Tc) of 316 K. The FM order origins from superexchange interaction between Mn and Te atoms. is half-metal (HM), spin-β electron semiconductor gap 1.462 eV. tends to show in-plane anisotropy (IPA), magnetic energy (MAE) −13.2 meV/f.u. good dynamical thermal stability. Moreover, presents half-metallic stability under cha...

The magnetic properties of doped pellets of poly(3-methylthiophene) showing room temperature ferromagnetic behaviour have been discussed in a previous article. The magnetic behaviour was attributed to a weak ferromagnetic phase, due to the superexchange interaction of polarons via the dopant anions. The Dzialoshinsky–Morya interaction among canted spins was proposed to explain the ferromagnetis...