Peierls distortion in alloys of quasi-one-dimensional conductors

We have calculated the value of the mean field Peierls transition temperature in a quasi-one-dimensional binary A-B alloy as a function of the relative concentration. This was done in the framework of the single-dimer coherent potential approximation. Reductions in the transition temperature are predicted for isoelectronic constituants.     

Fluctuation conductivity near a Peierls lattice distortion

There have been a number of recent theories for the fluctuation conductivity due to phonon softening near a one-dimensional Peierls lattice distortion. In these, the conductivity is evaluated for one or more Feynman response diagrams, with a resulting fluctuation conductivity which is positive, negative, or negligible. We calculate the conductivity using a conserving response theory which derives all of the response diagrams for any particular approximation to the electron propagator for the solid in thermodynamic equilibrium. Using this method in the mean-field theories to date, valid in principle for sufficiently high temperatures, the fluctuation conductivity due to phonon softening is positive and proportional to ($\text{T - T}{}_{\mathrm{p}}\text{)}{}^{\mathrm{<mtext>-</mtext><mtext>3</mtext><mtext>2</mtext>}}$, where T_p is the mean-field temperature scale in the one-dimensional Peierls system. This conductivity contribution is not due to the Fröhlich sliding mode.     

Higher order Peierls distortion of one-dimensional carbon skeletons

In some one-dimensional chains with metallic band structures the energetically most advantageous distortion opens an energy gap non-linear in the distortion. The absence of a linear Peierls effect is due to the symmetry of the degenerate pair of orbitals at the Fermi level: they do not interact directly in the distorted system. The effect provides a natural bridging of the one-dimensional polyacetylene (linearly Peierls-distorted) to the two-dimensional graphite (not distorted) carbon skeletons. The simple explanation bears some generality.     

Peierls distortion and electronic bands in phosphorus allotropes

A small difference between the rhombohedral phosphorus lattice (A-7 phase) and the simple cubic phase, as well as between phosphorene and the cubic structure, is used in order to construct their quasiparticle band dispersion. We exploit the Peierls idea of the Brillouin zone doubling/folding, which has been previously employed in consideration of semimetals of the V period and IV–VI semiconductors. In a common framework, individual properties of phosphorus allotropes are revealed.     

Stable monolayer of the RuO2 structure by the Peierls distortion

In this paper, we presented a stable two-dimensional ruthenium dioxide monolayer by using first-principles calculations within density functional theory. In contrast to ordinary hexagonal and octahedral structures of metal dichalcogenides, RuO₂ is stable in the distorted phase of the structure as a result of occurring charge density wave. A comprehensive analysis including the calculation of vibration frequencies, mechanical properties, and ab initio molecular dynamics at 300?K affirms that RuO₂ monolayer structure is stable dynamically and thermally and convenient for applications at room temperature. We also investigated the electronic and optical properties of RuO₂ and it is found that RuO₂ has of 0.74?eV band gap which is in the infrared region and very suitable for infrared detectors.     

An effect of the Peierls lattice distortion on the impurity distribution

Unlike most of the previous investigations devoted to the effect of a random distribution of nonmagnetic impurities on the Peierls distortion, we study here a converse effect, that of a 2k_F-distortion (k_F - Fermi wavevector) of the impurity distribution arising as a result of the Peierls distortion of the host lattice. An enhancement of both the electronic gap and phason effective mass is obtained. The conditions for the occurence of the aforementioned distortion are also discussed.     

Incompatibility of BCS pairing and the Peierls distortion in linear chain systems

We have solved the coupled gap equations for a one dimensional electron gas which can undergo both a Peierls insulating and a BCS superconducting transition. We find that, except for a very special case, (i) only one of the order parameters can be non-vanishing and (ii) there is only one critical temperature. We conclude that, independent of the pairing interaction strength, if the Peierls transition occurs, there can be no BCS superconductivity, and conversely.     

Peierls distortion in trans polyacetylene: Evidence from infrared intensities

It is shown that from the polarization properties of the infrared spectrum of oriented pristine trans polyacetylene clear evidence of Peierls distortion is obtained. Moreover, it is shown that during CH stretching and in-plane bending CC bonds develop relevant charge fluxes. Infrared intensity studies indicate the existence of an unusual charge mobility.     

Peierls distortion and vibrational spectra in undoped and doped trans-polyacetylene

We analyze the conditions under which the vibrational spectrum can provide information on the existence of the Peierls distortion in undoped trans-polyacetylene. If in the doped material sections of undimerized chains are generated, calculations predict a Raman active A_g band approximately between 1300-1250 cm^?1.     

Correlation mediated superconductivity in a Spin Peierls phase of the Hubbard model

We explore the consequences of a mapping of the Hubbard Hamiltonian with a view to finding possible superconducting phases. The transformation pairs up all the sites and is therfore a much more natural starting point for describing a Spin Peierls transition, generating enhanced singlet correlations for this pairing, than it is for describing the Resonating Valence Bond (RVB) state of Anderson. We show that in the less than half filling case, an effective non-linear hopping Hamiltonian is quite useful in describing half of the electrons. This effective Hamiltonian can show a form of superconducting instability when nearest neighbour hopping is introduced to stabilise it. This superconducting phase seems to be a very unlikely possibility for the standard Hubbard model.     

Lattice distortion (Peierls Transition) caused by spin interaction in the chaotic impurity system of a semiconductor

The effect of an elastic spontaneous distortion of the crystal lattice of a doped semiconductor Ge:As near the insulator–metal (IM) phase transition has been discovered. The effect is manifested in the electron spin resonance (ESR) of neutral As atoms as a splitting of the single resonance absorption line. It observed at electron concentrations in the range 0.8 < n/n_C < 1 at low temperatures T < 100 K (n_C = 3.7 × 10¹⁷ cm^‐3 is the critical electron concentration for the IM phase transition). The splitting is the strongest along each of the six [110] directions, which indicates that the local lattice distortion occurs just in these directions. As a result, a sample is possibly divided into separate domains differing in the directions of compressive or tensile deformations. A study of concentration, temperature, and angular dependences of the effect has shown that the phenomenon discovered can be understood in terms of the Peierls spin transition model.     

An exact limit for the Peierls distortion energy in an antiferromagnetic chain by means of a renormalization procedure

A renormalization procedure gives a rigorous upper bound for the ground-state energy per spin for a Peierls-distorted antiferromagnetic chain with Heisenberg interaction.     

Correlation length of quasiperiodic vortex lattices

We investigated vortex-lattice dynamics in superconducting Nb thin films with different quasiperiodic arrays of magnetic pinning centers. The mixed-state magnetoresistance exhibits minima for well-defined applied fields, related to matching effects between the vortex lattice and those arrays. The results show that critical matching can originate at a local scale. For fractal arrays, the vortex-lattice correlation length is longer and the minima are deeper, close to those of periodic arrays.     

Peierls Instability of the Lieb Lattice

JETP Letters - It is shown that the energy of the electron system in the two-dimensional Lieb lattice decreases owing to displacements of the edge atoms from the lattice sites along the edges. This...