CDW fluctuations and the pseudogap in the single-particle conductivity of quasi-1D Peierls CDW systems: II

Kupčić, Ivan; Rukelj, Zoran; Barišić, S.

doi:10.1088/0953-8984/26/19/195601

Cited by 7 publications

(10 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…58 Here the latter seems most relevant as fluctuating charge is observed in α-(BEDT-TTF) 2 I 3 already at room temperature. 27 According to Kupčić et al 61 fluctuations have little influence on the low-temperature value of the theoretical order parameter 2∆(0), but substantially lower the critical temperature and thus strongly affect the 2∆(0)/T c ratio. DC transport in the CO phase of α-(BEDT-TTF) 2 I 3 therefore points towards a predominantly mean-field-like behavior.…”

Section: B Evolution Of the Low-temperature Transport Gap In Presencmentioning

confidence: 99%

Semimetallic and charge-ordered α−(BEDT-TTF)2I3 : On the role of disorder in dc transport and dielectric properties

et al. 2017

View full text Add to dashboard Cite

α-(BEDT-TTF)2I3 is a prominent example of charge ordering among organic conductors. In this work we explore the details of transport within the charge-ordered as well as semimetallic phase at ambient pressure. In the high-temperature semimetallic phase, the mobilities and concentrations of both electrons and holes conspire in such a way to create an almost temperature-independent conductivity as well as a low Hall effect. We explain these phenomena as a consequence of a predominantly inter-pocket scattering which equalizes mobilities of the two types of charge carriers. At low temperatures, within the insulating charge-ordered phase two channels of conduction can be discerned: a temperature-dependent activation which follows the mean-field behavior, and a nearestneighbor hopping contribution. Together with negative magnetoresistance, the latter relies on the presence of disorder. The charge-ordered phase also features a prominent dielectric peak which bears a similarity to relaxor ferroelectrics. Its dispersion is determined by free-electron screening and pushed by disorder well below the transition temperature. The source of this disorder can be found in the anion layers which randomly perturb BEDT-TTF molecules through hydrogen bonds.

show abstract

Section: B Evolution Of the Low-temperature Transport Gap In Presencmentioning

confidence: 99%

Semimetallic and charge-ordered α−(BEDT-TTF)2I3 : On the role of disorder in dc transport and dielectric properties

et al. 2017

View full text Add to dashboard Cite

show abstract

“…[11] An alternative to this oversimplified description of the damping effects at ω < |E F | is the microscopic memoryfunction approach. [1,29,42] In this approach the intraband memory function is calculated by using the highenergy expansion of the RPA irreducible 4 × 4 currentcurrent correlation functions π intra µν (q, ω) in Eq. (A7).…”

Section: Microscopic Treatment Of Relaxation Processesmentioning

confidence: 99%

Damping effects in doped graphene: The relaxation-time approximation

Kupčić

2014

Phys. Rev. B

View full text Add to dashboard Cite

The dynamical conductivity of interacting multiband electronic systems derived in Ref. 1 is shown to be consistent with the general form of the Ward identity. Using the semiphenomenological form of this conductivity formula, we have demonstrated that the relaxation-time approximation can be used to describe the damping effects in weakly interacting multiband systems only if local charge conservation in the system and gauge invariance of the response theory are properly treated. Such a gauge-invariant response theory is illustrated on the common tight-binding model for conduction electrons in hole-doped graphene. The model predicts two distinctly resolved maxima in the energyloss-function spectra. The first one corresponds to the intraband plasmons (usually called the Dirac plasmons). On the other hand, the second maximum (π plasmon structure) is simply a consequence of the van Hove singularity in the single-electron density of states. The dc resistivity and the real part of the dynamical conductivity are found to be well described by the relaxationtime approximation, but only in the parametric space in which the damping is dominated by the direct scattering processes. The ballistic transport and the damping of Dirac plasmons are thus the questions that require abandoning the relaxation-time approximation.

show abstract

“…The solution of this integral equation can be obtained by iteration and shown in powers of λ 2 . Evidently, this method represents the highenergy expansion of the auxiliary electron-hole propagator 0 ν (k,k + ,iω n ,iω n+ ) [31]. It is characterized by explicit control of the law of conservation of energy and momentum and by precise characterization of the elementary excitations in the electron-phonon system under consideration, in both Kubo formulas for the conductivity tensor.…”

Section: A Formal Solutionmentioning

confidence: 99%

“…It is instructive first to determine the Boltzmann spectral representation of the conductivity tensor from the previous section for H = H 1 , the case which is of primary interest in graphene for frequencies ω ≈ ω LOq . We combine the iterative solution of the quantum transport equation 24with the electron-hole self-energy conductivity formula (31), and then show the kand ω-dependent memory function M(k,q,ω) ≈ M α (k,ω) and the ω-dependent memory function M α (ω) from Eqs. (32) and (33) in terms of the electron-hole self-energy (k,q,ω,ε) ≈ α (k,ω,ε).…”

Section: Weak Electron-phonon Interactionsmentioning

confidence: 99%

See 1 more Smart Citation

General theory of intraband relaxation processes in heavily doped graphene

Kupčić

2015

Phys. Rev. B

View full text Add to dashboard Cite

The frequency and wave-vector-dependent memory function in the longitudinal conductivity tensor of weakly interacting electronic systems is calculated by using an approach based on quantum transport equations. In this paper, we show that there is a close relation between the single-electron self-energy, the electron-hole pair self-energy, and the memory function. It is also shown in which way singular long-range Coulomb interactions, together with other q ≈ 0 scattering processes, drop out of both the memory function and the related transport equations. The theory is illustrated on heavily doped graphene, which is the prototype of weakly interacting single-band electron-phonon systems. A steplike increase of the width of the quasiparticle peak in angle-resolved photoemission spectra at frequencies of the order of the frequency of in-plane optical phonons is shown to be consistent with the behavior of an intraband plasmon peak in the energy loss spectroscopy spectra. Both anomalies can be understood as a direct consequence of weak electron scattering from in-plane optical phonons.

show abstract

CDW fluctuations and the pseudogap in the single-particle conductivity of quasi-1D Peierls CDW systems: II

Cited by 7 publications

References 38 publications

Semimetallic and charge-ordered α−(BEDT-TTF)2I3 : On the role of disorder in dc transport and dielectric properties

Semimetallic and charge-ordered α−(BEDT-TTF)2I3 : On the role of disorder in dc transport and dielectric properties

Damping effects in doped graphene: The relaxation-time approximation

General theory of intraband relaxation processes in heavily doped graphene

Contact Info

Product

Resources

About