Polarons

Devreese, Jozef T.

doi:10.1002/3527600434.eap347

Cited by 92 publications

(144 citation statements)

References 148 publications

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“…The possibility of two polarons forming bound pairs, or bipolarons, opens a whole new dimension in polaron physics [108,109]. The two major competing factors are the phonon-mediated attraction between the polarons that favours paring and direct Coulombic repulsion that prevents pairing.…”

Section: Bipolaronmentioning

confidence: 99%

Path Integrals in the Physics of Lattice Polarons

Kornilovitch

2007

Polarons in Advanced Materials

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Summary.A path-integral approach to lattice polarons is developed. The method is based on exact analytical elimination of phonons and subsequent Monte Carlo simulation of self-interacting fermions. The analytical basis of the method is presented with emphasis on visualization of polaron effects, which path integrals provide. Numerical results on the polaron energy, mass, spectrum and density of states are given for short-range and long-range electron-phonon interactions. It is shown that certain long-range interactions significantly reduce the polaron mass, and anisotropic interactions enhance polaron anisotropy. The isotope effect on the polaron mass and spectrum is discussed. A path-integral approach to the Jahn-Teller polaron is developed. Extensions of the method to lattice bipolarons and to more complex polaron models are outlined.

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Section: Bipolaronmentioning

confidence: 99%

Path Integrals in the Physics of Lattice Polarons

Kornilovitch

2007

Polarons in Advanced Materials

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“…The nature of this hole centre can most likely be referred to as a bound hole polaron. 23 An electron transfer to the Yb-ion through the CT process will cause an outward displacement of the surrounding anions. The hole left behind may then be trapped in a (self-induced) potential well.…”

Section: Uv Irradiation Of Rhenium Grown Yb:yagmentioning

confidence: 99%

Charge transfer processes and ultraviolet induced absorption in Yb:YAG single crystal laser materials

Rydberg¹,

Engholm²

2013

Journal of Applied Physics

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Charge transfer (CT) transitions and UV induced color centers in Yb:YAG single crystals have been investigated. A simultaneous pair formation of a stable Yb 2þ ion and a hole related ðO À Þ color center (hole polaron) are observed through a CT-process. Slightly different types of hole related color centers are formed in Yb:YAG crystals containing small levels of iron impurities. Furthermore, excitation spectroscopy on the UV irradiated Yb:YAG samples could confirm an energy transfer process between Yb 3þ and Yb 2þ ions. The findings are important for an increased knowledge of the physical loss mechanisms observed in Yb-doped laser materials, such as the nonlinear decay process in Yb:YAG crystals as well as the photodarkening phenomenon in Yb-doped fiber lasers. V C 2013 AIP Publishing LLC. [http://dx

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“…This supposition is in agreement with the anti-adiabatic limit for small polarons, where ions adiabatically follow the motion of electrons. 26 Following this approach, the external electric field applied in the ESM experiment between the tip and the counter electrode should induce a dipole moment of the small polarons 27 (as schematically shown in Figure 5) and their ordering along with the true ionic ESM response. This contribution can be more complex in the case when local Li/Mn ratio below the tip can exceed the first order Jahn-Teller distortion threshold (average Mn nþ oxidation state 3.5) and induce the lattice transformation.…”

Section: Non-vegard Contributionsmentioning

confidence: 99%

Li transport in fresh and aged LiMn2O4 cathodes via electrochemical strain microscopy

Luchkin

Romanyuk

Ivanov

et al. 2015

Journal of Applied Physics

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Transport properties of Li þ mobile ions in fresh and aged LiMn 2 O 4 battery cathodes were studied at the nanoscale via electrochemical strain microscopy (ESM), time spectroscopy, and voltage spectroscopy mapping. Both Vegard and plausible non-Vegard contributions to the ESM signal were identified in electrochemical hysteresis loops obtained on fresh and aged samples. In the fresh cathodes, the Vegard contribution dominates the signal, while in the aged samples different shape of hysteresis loops indicates an additional plausible non-Vegard contribution. Non-uniform spatial distribution of the electrochemical loop opening in LiMn 2 O 4 particles studied in the aged samples indicates stronger variation of the Li diffusion coefficient at the microscale as compared to the fresh specimens. Time spectroscopy measurements revealed a suppression of the local Li diffusivity in aged samples. The mechanisms of the cathode aging are discussed in the context of observed nanoscale ESM response. V C 2015 AIP Publishing LLC. [http://dx

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Polarons

Cited by 92 publications

References 148 publications

Path Integrals in the Physics of Lattice Polarons

Path Integrals in the Physics of Lattice Polarons

Charge transfer processes and ultraviolet induced absorption in Yb:YAG single crystal laser materials

Li transport in fresh and aged LiMn2O4 cathodes via electrochemical strain microscopy

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