Strong Coupling Characterisation of Quasi-1D polarons in cylindrical QW-wires

Cataloged from PDF version of article.We retrieve, within the strong-coupling theory, the quasi-one dimensional analog of the standard optical polaron relevant to a cylindrical quantum well wire. Under the assumption of perfect confinement the ground state binding energy, effective polaronic mass and the phonon-coupling-induced potential well profiles are given as a function of the wire radius and the electron-phonon interaction strength

A variational study of the ground Landau level of the 2D Frohlich polaron in a magnetic field

The problem of a two-dimensional polaron in a magnetic field is retrieved within the framework of an improved variational approximation which sets up a fractional admixture of the strong- and weak-coupling counterparts of the coupled electron-phonon system. The formulation is based on the usage of an adiabatic polaronic wavefunction corrected by a variationally determined perturbative extension enabling the adiabatic ansatz to be extrapolated towards the weak-coupling regime. The trial state derived here accounts for the magnetic field intensity not only in the electron part of the Hamiltonian, but also within the context of the part of the Hamiltonian describing the coupling of the electron to the phonon field

Energy and mass of 3D and 2D polarons in the overall range of the electron-phonon coupling strength

The ground-state characterization of the polaron problem is retrieved within the framework of a variational scheme proposed previously by Devreese et al for the bound polaron. The formulation is based on the standard canonical transformation of the strong coupling ansatz and consists of a variationally determined perturbative extension serving for the theory to interpolate in the overall range of the coupling constant. Specializing our considerations to the bulk and strict two-dimensional polaron models we see that the theory yields significantly improved energy upper bounds in the strong coupling regime and, moreover, extrapolates itself successfully towards the well-established weak coupling limits for all polaron quantities of general interest

Electronic properties of polypyrrole/polyindene composite/metal junctions

Junction properties between conducting polymer composites of polypyrrole/polyindene (PPy/PIn) with different conductivities and metals like Pt, Au, Al and In have been investigated. Rectifying junctions were observed for low work function metals, In and Al; however, high work function metals, Pt and Au, were observed to form ohmic contacts to PPy/PIn composite in the sandwich geometry. The rectifying behavior of the metal/composite/Pt junctions improved when the conductivity of the composite was decreased from 1 to 0.01 S/cm. Using the ideal Schottky theory various junction parameters have been determined. All planar junctions were ohmic regardless of the conductivities of the samples

Tomographic Probability Representation for States of Charge moving in Varying Field

The coherent and Fock states of a charge moving in varying homogeneous magnetic field are studied in the tomographic probability representation of quantum mechanics. The states are expressed in terms of quantum tomograms. The coherent states tomograms are shown to be described by normal distributions with varying dispersions and means. The Fock state tomograms are given in the form of probability distributions described by multivariable Hermite polynomials with time-dependent arguments.Comment: 12 pages, submitted to "Optics and Spectroscopy

Polaron effects on the binding energy of a hydrogenic impurity in a semiconductor quantum well

The polaron effect on the ground-state level of a hydrogenic impurity in a semiconductor quantum well is calculated as a function of the well thickness. The formulation is based on an extension of the strong-coupling polaron theory and covers the overall range of the electron-phonon coupling strength. It is observed that in a GaAs-based quantum structure the phonon-induced shift in the binding energy is smaller than that in the bulk case except for too narrow well sizes.Publisher's Versio