Spectral densities and diagrams of states of one-dimensional ionic Pauli conductor

Abstract

We focus on the features of spectra and diagrams of states obtained via exact diagonalization technique for finite ionic conductor chain in periodic boundary conditions. One dimensional ionic conductor is described with the lattice model where ions are treated within the framework of "mixed" Pauli statistics. The ion transfer and nearest-neighbour interaction between ions are taken into account. The spectral densities and diagrams of states for various temperatures and values of interaction are obtained. The conditions of transition from uniform (Mott insulator) to the modulated (charge density wave state) through the superfluid-like state (similar to the state with the Bose-Einstein condensation observed in hard-core boson models) are analyzed.

Diagrams of State for One-Dimensional Hydrogen-Bonded Proton Conductor

“…The protons only occupy some of the positions available (while other positions remain unoccupied) that is a general feature of ordered phases that exist in superionic crystals. Similar effect was found for ionic and proton conductors described by the analogous models in frames of Fermi statistics [13,14] as well as for the Pauli ionic conductor [18]. Keeping this in mind we will call this state CDW though the doubling of lattice period is not observed (while it is observed in "real" CDW phases).…”

“…For instance, the lattice model of ionic Pauli conductor is capable to describe the appearance of superfluid-like state (that may correspond to superionic phase) in the system even in the absence of interaction between particles [16,17]. While turning on interaction allows to describe more complex behaviour including transition to CDWlike state [18]. The lattice model of Pauli particles is similar to hard-core Bose-Hubbard model widely used for the description of physical phenomena in optical lattices as well as ionic conductivity and intercalation phenomena [19].…”

“…We pay special attention to the latter ones since according to experiments [21] and quantum-chemical calculations [22,23] they can be significant in real systems and therefore may affect the system's behaviour considerably. Moreover, for the case of ionic Pauli conductor the short-range interactions are responsible for the transition to CDW-like state [18]. Analyzing the single-particle spectral densities of protons in the finite 1D hydrogen-bonded chain and their changes with temperature at different concentration of protons we obtain the diagrams of state.…”