Non-Fermi liquid behavior and scaling of the low-frequency suppression in the optical conductivity spectra of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CaRuO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Lee, Yoon Sook; Yu, Jaejun; Lee, J. S.; Noh, T. W.; Gimm, Tae-Hyoung; Choi, Han-Yong; Eom, C. B.

doi:10.1103/physrevb.66.041104

Cited by 100 publications

(72 citation statements)

References 24 publications

(37 reference statements)

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“…The non-Fermi-liquid self energy we find bears an intriguing resemblance to the self energy inferred from optical conductivity measurements on SrRuO 3 [19,20,21].…”

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confidence: 71%

Spin Freezing Transition and Non-Fermi-Liquid Self-Energy in a Three-Orbital Model

et al. 2008

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A single-site dynamical mean field study of a three band model with the rotationally invariant interactions appropriate to the t2g levels of a transition metal oxide reveals a quantum phase transition between a paramagnetic metallic phase and an incoherent metallic phase with frozen moments. The Mott transitions occurring at electron densities n = 2, 3 per site take place inside the frozen moment phase. The critical line separating the two phases is characterized by a self energy with the frequency dependence Σ(ω) ∼ √ ω and a broad quantum critical regime. The findings are discussed in the context of the power law observed in the optical conductivity of SrRuO3.PACS numbers: 71.27.+a, 71.10.Hf , 71.10.Fd, 71.28.+d, 71.30.+h The 'Mott' metal-insulator transition plays a central role in the modern conception of strongly correlated materials [1,2]. Much of our understanding of this transition comes from studies of the one-band Hubbard model. Here, the transition is generically masked by antiferromagnetism, but if this is suppressed (physically, by introducing lattice frustration or mathematically, by examining an appropriately restricted class of theories such as the paramagnetic-phase single site dynamical mean field approximation [3]) a transition from a paramagnetic metal to a paramagnetic insulator is revealed. The properties of the paramagnetic metal phase near the transition play a central role in our understanding of the physics of correlated electron compounds.While one band models are relevant to many materials including the high temperature superconductors and some organic compounds, many systems of interest involve multiple correlated orbitals for which the physics is richer and less fully understood. Multiorbital models have been studied in Refs. [4,5,6,7,8,9,10]. New physics related to the appearance of magnetic moments has been considered in the context of the orbitally selective Mott transition which may occur if the orbital degeneracy is lifted [11,12,13,14,15], but for orbitally degenerate models it seems accepted that the essential concepts of a paramagnetic metal to paramagnetic insulator transition and a strongly correlated paramagnetic metal phase can be carried over from studies of the oneband situation.In this paper we show that this assumption is not correct. We use the single-site dynamical mean field approximation to demonstrate the existence of a quantum phase transition between a paramagnetic Fermi liquid and an incoherent metallic phase characterized by frozen local moments (a spin-spin correlation function which does not decay to zero at long times). We show that for densities per site n = 2, 3 the Mott transition occurs within or at the boundary of the frozen moment phase. As Costi and Liebsch have noted in the context of an orbitally selective Mott system, the presence of frozen moments may be expected to influence the Mott transition [15].The new phase appears for multiple orbitals, a different number of electrons than orbitals and a rotationally invariant on-site exchange U/3 > J...

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“…The non-Fermi-liquid self energy we find bears an intriguing resemblance to the self energy inferred from optical conductivity measurements on SrRuO 3 [19,20,21].…”

supporting

confidence: 71%

Spin Freezing Transition and Non-Fermi-Liquid Self-Energy in a Three-Orbital Model

et al. 2008

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“…2) exhibits metallic resistivity with a non-Fermi-liquid temperature dependence best described by a sub-linear form in its hightemperature range above 60 K, ρ(T ) ∝ T α with α = 0.74, in qualitative agreement with prior work that had yielded powerlaw exponents α = 1/2 and 3/2 for the high-and lowtemperature ranges, respectively. [8][9][10][11] This has been ascribed to the influence of spin fluctuations in proximity to a ferromagnetic quantum critical point. The resistivity of the CaMnO 3 film exhibits insulating, activated behavior (Fig.…”

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confidence: 99%

“…[8][9][10][11] and CaMnO 3 (Refs. [12][13][14][15] and show that a comparison between far-infrared and dc-MR measurements can yield insights into the origin of this behavior.…”

Section: Introductionmentioning

confidence: 99%

Far-infrared and dc magnetotransport of CaMnO3-CaRuO3superlattices

et al. 2011

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We report temperature and magnetic field dependent measurements of the dc resistivity and the far-infrared reflectivity (photon energies ω = 50 − 700 cm −1 ) of superlattices comprising 10 consecutive unit cells of the antiferromagnetic insulator CaMnO3, and 4 -10 unit cells of the correlated paramagnetic metal CaRuO3. Below the Néel temperature of CaMnO3, the dc resistivity exhibits a logarithmic divergence upon cooling, which is associated with a large negative, isotropic magnetoresistance. The ω → 0 extrapolation of the resistivity extracted from the FIR reflectivity, on the other hand, shows a much weaker temperature and field dependence. We attribute this behavior to scattering of itinerant charge carriers in CaRuO3 from sparse, spatially isolated magnetic defects at the CaMnO3-CaRuO3 interfaces. This field-tunable "transport bottleneck" effect may prove useful for functional metal-oxide devices.

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“…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.…”

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confidence: 92%

Bad Metals from Fluctuating Density Waves

et al. 2017

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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 ...

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Non-Fermi liquid behavior and scaling of the low-frequency suppression in the optical conductivity spectra ofCaRuO3

Cited by 100 publications

References 24 publications

Spin Freezing Transition and Non-Fermi-Liquid Self-Energy in a Three-Orbital Model

Spin Freezing Transition and Non-Fermi-Liquid Self-Energy in a Three-Orbital Model

Far-infrared and dc magnetotransport of CaMnO3-CaRuO3superlattices

Bad Metals from Fluctuating Density Waves

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