نتایج جستجو برای: polaron
تعداد نتایج: 1860 فیلتر نتایج به سال:
Nano-phasic Ba1-XSbXMnO3 have been synthesised through sol-gel citrate route. The XRD pattern has been found to be having some brown millerite phase along with pervoskite due to doping induced anti-site effect. The dependence of electrical transport at high temperatures have been studied employing thermal activation model, variable range hopping (VRH) and small polaron hopping model (SPH) to ac...
Keeping the full quantum nature of the problem, we compute the relaxation time of the Holstein polaron in one dimension after it was driven far from the equilibrium by a strong oscillatory pulse. Just after the pulse, the polaron's kinetic energy increases and subsequently exhibits a relaxation-type decrease with simultaneous emission of phonons. In the weak coupling regime, partial tunneling o...
Theoretical investigation of the polaron effects on the third-order susceptibility associated with the intersubband transition in the conduction band in a CdSe/ZnS quantum dot quantum well is presented. Contributions from the confined longitudinal optical (LO) and surface optical phonon modes are considered and the wave function is derived under the frame work of the perturbation theory. We car...
We show that spin-orbit coupling (SOC) gives rise to pairing instability in a highly polarized two-dimensional Fermi gas for an arbitrary interaction strength. The pairing instability can lead to a Fulde-Ferrell-Larkin-Ovchinnikov-like molecular state, which undergoes a first-order transition into a pairing state with zero center-of-mass momentum as the parameters are tuned. These pairing state...
We study a single polaron in the Su-Schrieffer-Heeger (SSH) model using four different techniques (three numerical and one analytical). Polarons show a smooth crossover from weak to strong coupling, as a function of the electron-phonon coupling strength λ, in all models where this coupling depends only on phonon momentum q. In the SSH model the coupling also depends on the electron momentum k; ...
We investigate the steady-state electronic transport through a suspended dimer molecule coupled to leads. When strongly coupled to a vibrational mode, the electron transport is enhanced at the phonon resonant frequency and higher order resonances. The temperature and bias determine the nature of the phonon-assisted resonances, with clear absorption and emission peaks. The strong coupling also i...
We report measurements of the resistivity in the ferromagnetic state of epitaxial thin films of La(1-x)Ca(x)MnO3 and the low-temperature specific heat of a polycrystalline La0.8Ca0.2MnO3. The resistivity below 100 K can be well fitted by rho-rho(0) = Eomega(s)/sinh (2)(hs/ 2k(B)T) with h(omega)(s)/k(B) approximately 80 K and E being a constant. Such behavior is consistent with small-polaron coh...
The standard polaron band model of doped organic semiconductors predicts that density-of-states shift into the π-π* gap to give a partially filled polaron band that pins the Fermi level. This picture neglects both Madelung and Hubbard interactions. Here we show using ultrahigh workfunction hole-doped model triarylamine-fluorene copolymers that Hubbard interaction strongly splits the singly-occu...
The rapid insertion and extraction of Li ions from a cathode material is imperative for the functioning of a Li-ion battery. In many cathode materials such as LiCoO2, lithiation proceeds through solid-solution formation, whereas in other materials such as LiFePO4 lithiation/delithiation is accompanied by a phase transition between Li-rich and Li-poor phases. We demonstrate using scanning transm...
Mn K-edge fluorescence data are presented for thin film samples (3000 Å) of Colossal Magnetoresistive (CMR) La0.67Ca0.33MnO3: as-deposited, and post-annealed at 1000 K and 1200 K. The local distortion is analyzed in terms of three contributions: static, phonon, and an extra, temperature-dependent, polaron term. The polaron distortion is very small for the as-deposited sample and increases with ...
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