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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"Polarons"”.
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Dynamics of finite momentum Bose polarons
We study the behavior of a finite-momentum impurity immersed in a weakly interacting Bose-Einstein condensate (BEC) of ultra-cold atoms near an interspecies Feshbach resonance. Using the time-dependent variational approach, we study both ground state properties and quench dynamics of the system …
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Infrared Absorption by Localized Polarons in the Sliver Halides
Made available in DSpace on 2015-05-12T21:41:44Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6808030.PDF: 3329990 bytes, checksum: 224ccd657a1bce119f04481caba960ab (MD5) Previous issue date: 1967
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Infrared absorption by localized polarons in the silver halides
The infrared absorption of silver halide crystals, induced by simultaneous illumination of the crystals with light whose energy exceeded the indirect band gap, was measured from 33 to 2000 cm-1 at temperatures from. 90 K to 40 0 K. The induced far infrared absorption was shown to be in agreement …
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New models of magnetic interactions for bound magnetic polarons in dilute magnetic semiconductors
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1990
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Atoms and Molecules Immersed in a Bose-Einstein Condensate
… their absolute ground state directly from Bose polarons, which are dressed fermionic ⁴⁰K impurities immersed in a ²³Na Bose-Einstein condensate. In contrast to Feshbach molecules, Bose polarons at negative scattering length are long-lived in the presence of the BEC. We demonstrate direct …
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The weakly coupled polaron
… of weakly coupled longitudinal optical polarons. By taking into consideration the contribution of the multi-phonon and the phonon-cross-exchange diagrams in the self-energy, a vertex correction has been made to the lowest order diagram. The real part and the imaginary part of the …
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Optical investigation of many-body interactions in transition metal dichalcogenide heterostructures
… dressed by a gate-tunable Fermi sea form exciton-polarons, which are sensitive to Coulomb and spin interactions. In addition, TMD moir´e devices provide a highly tunable platform to study strongly correlated electronic states. This thesis describes the use of magneto-optical polarisation-resolved …
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DESCRIPTION OF POLARONS IN LAYERED TRANSITION METAL OXIDES USING THE r2SCAN DENSITY FUNCTIONAL WITH FULLY NONLOCAL CORRECTIONS AND EFFECT OF STRAIN ON THE BAND GAP OF MONOLAYER MOLYBDENUM DISULFIDE
Defects in materials significantly influence their properties and enhance functionality. Hybrid functionals like HSE06, though effective for describing defects, face challenges in geometry optimization for large supercells. The r2SCAN+rVV10+U+Ud method provides a computationally efficient …
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Structural, magnetic and electric transport properties of metal substituted La₀.₇Sr₀.₃MnO₃
… interactions between electrons, phonons, and polarons"--Abstract, page iv.
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Probing the Dynamics of Pressure- and Magnetic Field -Tuned Transitions in Strongly-Correlated Electron Systems: Raman Scattering Studies
… Raman response betrays the formation of magnetic polarons above the Curie temperature Tc; and (iv) a ferromagnetic metal regime, characterized by a flat electronic continuum response.
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Theory and simulation of amorphous organic electronic devices
… which are controlled by the behavior of polarons (charged molecular states), and excitons (neutral molecular excited states). In this thesis we employ microscopic models of polaron and exciton processes to calculate macroscale phenomena in amorphous small molecular weight organic thin …
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Critical behavior and transport properties of lanthanum manganite
… consistent with thermally activated hopping of polarons. The charge carriers appear to consist of two different types which add according to the Nordheim-Gorter rule. The mixing fraction of the two populations around the transition temperature can be extracted with an effective medium approach. …
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Magnetic Resonance Studies of Free Radicals Generation and their Impact in Different Polymers
… the behavior of the charge carriers, especially polarons under the effect of magnetophoresis.</p>
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Dimers, Trimers and their Superpositions in a Bose-Fermi Mixture
… their evolution into strongly interacting Bose polarons with hybridized dimer and trimer character when we instead immerse an impurity concentration of K into a dense quantum bath of Na. We report a novel direct observation of a heteronuclear halo trimer, consisting of two lighter Na atoms and …
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Nonreciprocal phenomena in superconductivity
… a doped hole with a magnon (spin flip). Spin polarons have large effective mass and are spin 3/2 quasiparticles. The mechanism for their formation is kinetic frustration, and therefore their binding energy is proportional to the hopping t, which is the largest energy scale within a single …
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Complex phase behavior of exotic oxides: optical spectroscopy studies
… we observed that carriers are localized as small polarons in the high temperature paramagnetic phase, which contribute to the 'collision-limited' diffusive electronic Raman scattering response. The metal-insulator transition is characterized by a change in the low energy electronic Raman …
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Hall Potential Mapping of Conducting Ferroelectric Domain Walls
… carrier-lattice coupling associated with small polarons. <br/>The technique was further developed by utilising Kelvin probe force microscopy to map the topographic and electrostatic signal in isolation. Surface potential mapping of an ErMnO<sub>3</sub> single crystal confirms quantitative …
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Experimental investigations of excited-state dynamics in conjugated polymers using time-resolved laser spectroscopy
… and inherent loss of potential delocalised polarons in this system.
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Energy Level Alignment in Hybrid Bulk Heterojunctions and New Redox Mediators for Quantum Dot Solar Cells
… in TiO2 accept electrons from P3HT and form hole polarons in the polymer. This equilibrium charge separation alters energetics through the formation of interfacial dipoles and results in band bending that inhibits desired photoelectron injection into TiO2, limiting HBHJ solar cell performance. New …
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Triplet Exciton Management in Organic Electronic Devices
… the signal becomes dominated by free polarons, suggesting that charge separation may be a mechanism of luminescence quenching at high concentration. In many organic photovoltaic material systems triplets are low-lying states from which charge separation is not energetically favoured. …
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