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Bipolaron
About: Bipolaron is a research topic. Over the lifetime, 1335 publications have been published within this topic receiving 29154 citations. The topic is also known as: bipolarons.
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TL;DR: The case of polaron and bipolaron formation due to electron-phonon coupling on a lattice with soft non-linear intersite interactions was studied in this article, where the binding energy of the bipolaron was examined as a function of the degree of nonlinearity of the lattice.
Abstract: The case of polaron and bipolaron formation due to electron-phonon coupling was studied on a lattice with soft non-linear intersite interactions. The ground state of a system that consists of one or two electrons coupled to a non-linear lattice was obtained numerically. The binding energy of the bipolaron was examined as a function of the degree of the non-linearity of the lattice. A model was investigated where the interatomic interactions in the lattice are described by a double-well potential. This type of non-linear interaction strongly influences the bipolaron formation and generally improves its stability and increases its binding energy by permitting a local structural change of the lattice.
01 Jan 1987
TL;DR: In this article, the self-consistency of multi-electron states with lattice symmetry breaking is summarized and the discrete symmetries and corresponding selection rules for both radiative and nonradiative processes are discussed.
Abstract: The lattice relaxation theory generalized by us to include the self-consistency of multi-electron states with lattice symmetry-breaking is summarized. The discrete symmetries and corresponding selection rules for both radiative and nonradiative processes are discussed. The theoretically calculated probability of nonradiative decay of an electron-hole pair into a soliton pair and that of an electron (hole) into a polaron as well as the probability of soliton pair photogeneration is compared with results of numerical and laboratory experiments. The resonance Raman scattering data of cis-polyacetylene are interpreted in terms of a bipolaron model. The parameters involved are determined directly from experimental data.
TL;DR: In this paper, the localized vibrational modes around a bipolaron in cis-(CH)x are studied by using a two-dimensional extension of the SSH model that includes the bond-bending term.
Abstract: The localized vibrational modes around a bipolaron in cis-(CH)x are studied by using a two-dimensional extension of the SSH model that includes the bond-bending term. A number of additional modes have been found, compared with the results based on the standard SSH model. The amplitudes of the two directions (x and y direction) are comparable for most of the modes as in the trans-(CH)x case. The number of localized modes and their frequencies depend not only on the coupling constant, but also on the bond-bending term and the parameter t1 in removing the degeneracy of the ground state.
TL;DR: In this paper, the bipolaron theory of Cooper pairs suggests that there is a possibility for a superconducting phase to exist at low and high levels of doping and be absent at intermediate level of doping.
Abstract: It is shown that the bipolaron theory of Cooper pairs suggests that there is a possibility for a superconducting phase to exist at low and high levels of doping and be absent at intermediate level of doping. The results obtained imply possibly universal character of 1/8 anomaly.
TL;DR: In this paper, it was shown that a hyperfine field originating from the hydrogen nuclei in organic materials is necessary for observing OMAR by studying C60 sandwich devices using several different electrode materials.
Abstract: We experimentally test three existing models of organic magnetoresistance (OMAR) which are all based on carrier spin dynamics. We first prove that hyperfine field originating from the hydrogen nuclei in organic materials is necessary for observing OMAR by studying C60 sandwich devices using several different electrode materials. We show that C60, unlike many other organic semiconductors, does not exhibit any intrinsic OMAR effect. However, we find that as soon as the carriers in C60 are brought in proximity with hydrogen-containing compounds, either in the form of a polymeric electrode, or side-chain substituents, a weak OMAR effect is observed. Next, we perform charge-induced absorption and electroluminescence spectroscopy in a polyfluorene organic magnetoresistive device. Our experiments allow us to measure the singlet exciton, triplet exciton and polaron densities in a live device under an applied magnetic field, and to distinguish between three models of OMAR. These models are based on different spin-dependent interactions, namely exciton formation, triplet exciton-polaron quenching and bipolaron formation. We show that the singlet exciton, triplet exciton and polaron densities and conductivity all increase with increasing magnetic field. Our data are inconsistent with the exciton formation and triplet-exciton polaron quenching models.