Optical properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>β</mml:mi></mml:mrow><mml:mrow><mml:mi>″</mml:mi></mml:mrow></mml:msup></mml:mrow><mml:mo>−</mml:mo><mml:mo>(</mml:mo><mml:mi mathvariant="normal">ET</mml:mi><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">SF</mml:mi></mml:mrow><mml:mrow><mml:mn>5

Dong, Jian; Musfeldt, J. L.; Schlueter, John A.; Williams, Jack M.; Nixon, Paul; Winter, R.; Gard, Gary L.

doi:10.1103/physrevb.60.4342

Cited by 36 publications

(38 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It reveals a shoulder at 4800 cm-l and a strong electronic band around 9500 cm '1 [5]. These features are not observed in the spectrum of the superconductor or the metal [6,7]. At the same time, the lb spectra of the sttperconductor and metal are very similar.…”

Section: Introductionmentioning

confidence: 50%

Two-dimensional magnetic quantum oscillations observed in an organic metal

Hagel¹,

Wanka²,

Wosnitza³

et al. 2001

Synthetic Metals

View full text Add to dashboard Cite

The small chemical modKication of the counterion has a dramatic effect on the spectral and charge transport properties of these materials, and we discuss their electronic structure in terms of band structure, many-body effects, and dsorder. Based on structural dMerences in the anion pocket of the three salts, we conclude that the unusual electronic excitations observed in the .B''-{W&FsCHFCFZSO3 metal/insulator material are caused by disorder-reiated localization.Ke~words: Reflectio= spectroscopy, Organic conductors b~d on radical cation and/or anion salts

show abstract

Section: Introductionmentioning

confidence: 50%

Two-dimensional magnetic quantum oscillations observed in an organic metal

Hagel¹,

Wanka²,

Wosnitza³

et al. 2001

Synthetic Metals

View full text Add to dashboard Cite

show abstract

“…It is in fact observed that in a large number of bad metals the Drude peak in the optical conductivity moves away from ω = 0 as the temperature is increased, leading to a suppression of low frequency spectral weight. This phenomenon is seen in ruthenates [16,17], cobaltates [18,19], cuprates [20][21][22][23][24], vanadates [25,26], manganates [27,28], nickelates [29] and organic conductors [30,31]. The behavior is illustrated in figure 1 below.…”

mentioning

confidence: 93%

Bad Metals from Fluctuating Density Waves

et al. 2017

View full text Add to dashboard Cite

Bad metals have a large resistivity without being strongly disordered. In many bad metals the Drude peak moves away from zero frequency as the resistivity becomes large at increasing temperatures. We catalogue the position and width of the 'displaced Drude peak' in the observed optical conductivity of several families of bad metals, showing that ω peak ∼ ∆ω ∼ k B T /ħ h. This is the same quantum critical timescale that underpins the T -linear dc resistivity of many of these materials. We provide a unified theoretical description of the optical and dc transport properties of bad metals in terms of the hydrodynamics of short range quantum critical fluctuations of incommensurate density wave order. Within hydrodynamics, pinned translational order is essential to obtain the nonzero frequency peak. Check for updates doi:10.21468/SciPostPhys.3.3.025 Bad metals are defined by the fact that if their electrical resistivity is interpreted within a conventional Drude formalism, the corresponding mean free path of the quasiparticles is so short that the Boltzmann equation underlying Drude theory is not consistent [1][2][3]. As such, bad metals pose a long-standing challenge to theory. In this work we show that the hydrodynamics of phase-fluctuating charge density waves can lead to bad metallic behavior. Hydrodynamics is a tightly constrained formalism for the low energy and long wavelength dynamics of media [4,5]. Non-quasiparticle media, in particular, exhibit fast local thermalization leading to extended hydrodynamics regimes. Phase fluctuations in the density wave can be robustly incorporated into this description and will be essential in order for the states to be metallic, rather than insulating. We will use the hydrodynamic framework to explain observed dc and optical transport behavior that is common to several families of bad metal materials.Recent work has emphasized that the absence of quasiparticles is not sufficient to obtain a bad metal [6]. If the total momentum of the charge carriers is long-lived, then the resistivity will be small even if all single-particle excitations decay rapidly. The importance of the fate of momentum for transport has long been appreciated [7,8], but has acquired renewed relevance 1 SciPost Phys. 3, 025 (2017) in the context of modern unconventional metals, e.g. [9,10]. Two previously considered scenarios for removing the long-lived momentum (sound) mode from the collective description of charge transport are as follows. Firstly, that the low energy, non-quasiparticle, description of bad metals is strongly non-translationally invariant and hence momentum is absent from the hydrodynamic description [6]. Secondly, that an emergent particle-hole symmetry at low energies decouples charge transport from momentum [11]. These mechanisms do not seem to be at work in bad metals. The resistivity of bad metals is not typically strongly dependent on the strength of disorder and some bad metals appear to be relatively clean. Emergent particle-hole symmetry does not decouple momentum ...

show abstract

“…This finding is in qualitative agreement with experimental data on and ␤Љ organic salts. [11][12][13][14] Our results are relevant to the optical response of sodium vanadates, such as ␤-Na 0.33 V 2 O 3 , which also display charge ordering.…”

mentioning

confidence: 93%

“…In particular, the optical conductivity spectra display a broad midinfrared band and the near absence of a Drude-like peak. 11 This is in contrast to conventional metals, for which the total spectral weight is dominated by a Drude peak.…”

mentioning

confidence: 94%

Metal-insulator transition and charge ordering in the extended Hubbard model at one-quarter filling

Calandra

Merino²,

McKenzie³

2002

Phys. Rev. B

View full text Add to dashboard Cite

We study, with exact diagonalization, the zero temperature properties of the quarter-filled extended Hubbard model on a square lattice. We find that increasing the ratio of the intersite Coulomb repulsion, V, to the bandwidth drives the system from a metal to a charge ordered insulator. The evolution of the optical conductivity spectrum with increasing V is in agreement with the observed optical conductivity of several layered molecular crystals with the and ␤Љ crystal structures. DOI: 10.1103/PhysRevB.66.195102 PACS number͑s͒: 71.27.ϩa, 71.30.ϩh Charge ordering in strongly correlated electron systems is currently under intense investigation. Charge ordering is relevant to a broad range of materials including cuprates, 1 manganates, 2 magnetite, 3 vanadium oxides, 4 and Bechgaard salts. 5 and ␤Љ types of layered molecular crystals based on molecules such as BEDT-TTF ͑bisethylenedithio-tetrathiafulvalene͒ ͑Ref. 6͒, display charge ordering, metallic, and superconducting phases close to each other. 7 Charge ordering driven by a strong intersite Coulomb repulsion 8,9 is possible in crystals with and ␤Љ arrangements of BEDT-TTF molecules because their bands are quarter-filled with holes, in contrast to the well-studied -type, crystals for which strong dimerization of the molecules lead to a halffilled band. 10 -type crystals undergo a transition from a metal to a charge-ordered insulator as the temperature, pressure, uniaxial stress, or anion is varied. 7,8 Furthermore, the metallic phase exhibits features characteristic of a strongly correlated system. In particular, the optical conductivity spectra display a broad midinfrared band and the near absence of a Drude-like peak. 11 This is in contrast to conventional metals, for which the total spectral weight is dominated by a Drude peak.In this paper, we use the results of an exact diagonalization study of the relevant extended Hubbard model to argue that the intersite Coulomb repulsion is responsible for the observed metal-insulator transition in the and ␤Љ crystals. We show how the Drude weight decreases as the intersite Coulomb repulsion V is increased, until, at a finite value of V, a transition to an insulating phase occurs. Simultaneously, long-range charge ordering gradually sets in. We further find that a redistribution of the optical conductivity spectra occurs close to the metal-insulator transition. This finding is in qualitative agreement with experimental data on and ␤Љ organic salts. 11-14 Our results are relevant to the optical response of sodium vanadates, such as ␤-Na 0.33 V 2 O 3 , which also display charge ordering.The quarter-filled extended Hubbard model on a square lattice is the simplest strongly correlated model that can potentially describe the competition between metallic, superconducting, and insulating phases in the and ␤Љ materials. 15,16 The Hamiltonian is ͑1͒where c i † creates an electron of spin at site i. For Vϭ0, previous calculations suggested that the system is metallic with no charge order. 17 In the limit of U,Vӷt the double o...

show abstract

Optical properties ofβ″−(ET)2SF5

Cited by 36 publications

References 54 publications

Two-dimensional magnetic quantum oscillations observed in an organic metal

Two-dimensional magnetic quantum oscillations observed in an organic metal

Bad Metals from Fluctuating Density Waves

Metal-insulator transition and charge ordering in the extended Hubbard model at one-quarter filling

Contact Info

Product

Resources

About