Superconductivity, spin and charge order, and quantum criticality in correlated electron materials

Maple, M. B.; Hamlin, J. J.; Zocco, D. A.; Janoschek, M.; Baumbach, Ryan; White, B. D.; Fisher, I. R.; Chu, Jiun‐Haw

doi:10.1051/epjconf/20122300012

Cited by 4 publications

(4 citation statements)

References 36 publications

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“…As a future outlook, it seems particularly interesting to explore this novel scenario in the proximity of superconductivity, eventually competing or coexisting with CDW order. In fact, superconductivity appears at ∼2 K in some of the rare-earth tritellurides if the CDW is suppressed by applied pressure (41,42). Moreover, it would be intriguing to address in a wider context the effects of band hybridization in materials such as the iron-based superconductors (34), in which density-wave order and superconductivity interplay on a microscopic scale.…”

Section: Discussionmentioning

confidence: 99%

Alternative route to charge density wave formation in multiband systems

Eiter

Lavagnini

Hackl

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

103

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Charge and spin density waves, periodic modulations of the electron, and magnetization densities, respectively, are among the most abundant and nontrivial low-temperature ordered phases in condensed matter. The ordering direction is widely believed to result from the Fermi surface topology. However, several recent studies indicate that this common view needs to be supplemented. Here, we show how an enhanced electron-lattice interaction can contribute to or even determine the selection of the ordering vector in the model charge density wave system ErTe 3 . Our joint experimental and theoretical study allows us to establish a relation between the selection rules of the electronic light scattering spectra and the enhanced electron-phonon coupling in the vicinity of band degeneracy points. This alternative proposal for charge density wave formation may be of general relevance for driving phase transitions into other brokensymmetry ground states, particularly in multiband systems, such as the iron-based superconductors.electron-phonon interactions | nonconventional mechanism | Raman spectroscopy | solid-solid phase transitions T he common view of charge density wave (CDW) formation was originally posed in the work by Kohn (1). Using Kohn's reasoning (1), the tendency to ordering is particularly strong in low dimensions, because the Fermi surface has parallel parts, referred to as nesting. This nesting leads to a divergence in the Lindhard susceptibility, determining the magnitude and direction of the ordering vector Q (2). This divergence in the electronic susceptibility is conveyed to the lattice by the electron-phonon coupling: a phonon softens to zero frequency at Q, and a static lattice distortion develops when the system enters the CDW state, a behavior known as the Kohn anomaly.However, several publications raise the question as to whether nesting alone is sufficient to explain the observed ordering direction Q (3-7), particularly in dimensions higher than 1D. A central question is whether the selection of the CDW ordering vector is always driven by an electronic instability or if the ordering vector could, instead, be determined by a lattice distortion driven by some other mechanism exploiting the role of the electron-phonon coupling. In the latter case, the selected ordering vector would not necessarily nest the Fermi surface. The importance of strongly momentum-dependent electron-phonon coupling on CDW formation was pointed out in refs. 3 and 4, where the relevance of the Fermi surface for determining the ordering vector was indeed found to decrease as the coupling strength increases. In a recent paper on inelastic X-ray scattering measurements on 2H-NbSe 2 , acoustic phonons were observed to soften to zero frequency over an extended region around the CDW ordering vector (8). The authors argue that this behavior is not consistent with a Kohn anomaly picture, where sharp dips are expected (8). Therefore, the phonon softening must be driven by another mechanism, which they identify as a wave vector-dependent e...

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Section: Discussionmentioning

confidence: 99%

Alternative route to charge density wave formation in multiband systems

Eiter

Lavagnini

Hackl

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

103

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“…Occasionally, the CDW phase is in close proximity to other phases such as superconductivity. 2,3 The rare-earth tritellurides 4 RTe 3 are excellent model systems for systematic studies of the underlying physics for the wide range of tunable parameters such as transition temperature T CDW , Fermi surface shape, c-axis coupling, anisotropic or weak versus strong electronphonon coupling. [5][6][7][8][9][10][11][12] These compounds have an orthorhombic crystal structure (Cmcm space group) commonly thought of as being 'weakly' orthorhombic, i.e.…”

Section: Introductionmentioning

confidence: 99%

Charge density wave modulation and gap measurements inCeTe3

et al. 2016

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We present a study of charge density wave (CDW) ordering in CeTe3 at room temperature using a scanning tunneling microscope and Raman spectroscopy. Two characteristic CDW ordering wavevectors obtained from the Fourier analysis are assessed to be |c * − q| = 4.19 nm −1 and |q| = 10.26 nm −1 where |c * | = 2π/c is the reciprocal lattice vector. The scanning tunneling spectroscopy measurements, along with inelastic light (Raman) scattering measurements, show a CDW gap ∆max of approximately 0.37 eV. In addition to the CDW modulation, we observe an organization of the Te sheet atoms in an array of alternating V-and N-groups along the CDW modulation, as predicted in the literature.

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“…As a future outlook, it seems particularly interesting to explore this novel scenario in the proximity of superconductivity, eventually competing or coexisting with CDW order. In fact, superconductivity at approximately 2 K appears in some of the rare earth tri-tellurides if the CDW is suppressed by applied pressure 41,42 . Moreover, it would be intriguing to address in a wider context the effects of band hybridization in materials such as the iron-based superconductors 34 , in which density-wave order and superconductivity interplay on a microscopic scale.…”

Section: Discussionmentioning

confidence: 99%

Alternative route to charge density wave formation in multiband systems

Eiter,

Lavagnini,

Hackl

et al. 2012

Preprint

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View full text Add to dashboard Cite

Charge and spin density waves, periodic modulations of the electron and magnetization densities, respectively, are among the most abundant and non-trivial low-temperature ordered phases in condensed matter. The ordering direction is widely believed to result from the Fermi surface topology. However, several recent studies indicate that this common view needs to be supplemented. Here, we show how an enhanced electron-lattice interaction can contribute to or even determine the selection of the ordering vector in the model charge density wave system ErTe3. Our joint experimental and theoretical study allows us to establish a relation between the selection rules of the electronic light scattering spectra and the enhanced electron-phonon coupling in the vicinity of band degeneracy points. This alternative proposal for charge density wave formation may be of general relevance for driving phase transitions into other broken-symmetry ground states, particularly in multiband systems such as the iron based superconductors.

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Superconductivity, spin and charge order, and quantum criticality in correlated electron materials

Cited by 4 publications

References 36 publications

Alternative route to charge density wave formation in multiband systems

Alternative route to charge density wave formation in multiband systems

Charge density wave modulation and gap measurements inCeTe3

Alternative route to charge density wave formation in multiband systems

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