Sliding Density Wave in Sr
 14
 Cu
 24
 O
 41
 Ladder Compounds

Blumberg, G.; Littlewood, P. B.; Gozar, A.; Dennis, B. S.; Motoyama, N.; Eisaki, H.; Uchida, S.

doi:10.1126/science.1070481

Cited by 111 publications

(103 citation statements)

References 29 publications

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“…The peak in 1/T 1 and the subsequent spectral change at lower temperatures de-scribed here are very similar to what were observed in the lightly hole-doped two-leg ladder compound Sr 24 Cu 24 O 41 [28]. This material is an insulator at low temperatures and there are evidences for charge order in the ladder planes from both the frequency dependent conductivity [29,30] and the development of fine structure in the NQR spectrum [28]. Thus the peak in 1/T 1 in this material is most likely caused by collective fluctuations of electronic charge.…”

supporting

confidence: 67%

Charge Freezing in the Zigzag ChainPrBa2Cu4O
Fujiyama
¹
,
Takigawa
²
,
Horii
³

2003
Phys. Rev. Lett.
31
3
25
0
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We report nuclear quadrupole resonance (NQR) studies on the chain Cu sites of PrBa2Cu4O8, a quasi-one-dimensional conductor with a nearly quarter-filled band. The nuclear spin-lattice relaxation rate 1/T1 shows a pronounced peak near 100 K caused by fluctuations of electric field gradient (EFG). Similar peak was observed for the spin-echo decay rate 1/T2, however, at a different temperature near 50 K. These results and broadening of the NQR spectrum at low temperatures indicate that slow charge fluctuations of either electronic or ionic origin freeze gradually at low temperatures.There has been increasing interest in quasi-onedimensional (Q1D) correlated electrons. Theoretical studies on generalized Hubbard or t-J models for chains and ladders have revealed rich phase diagram associated with various instabilities towards Mott localization, spin density wave, charge order, and superconductivity [1,2,3] These two compounds show contrasting transport behavior. Pr124 is a highly anisotropic Q1D metal showing extremely large in-plane resistivity anisotropy ρ a /ρ b ∼ 1000 at 4 K [12,13,14], where b is along the chain direction and a is perpendicular to it within the CuO 2 plane. Although ρ b shows monotonic metallic temperature dependence, ρ a exhibits a broad peak near 130 K, indicating incoherent transport perpendicular to the chains at high temperatures. The angle resolved photoemission spectra (ARPES) [15] also revealed a clear one-dimensional dispersion which crosses the Fermi level near the momentum k b ≃ π/4, pointing to a nearly quarter-filled conduction band. In Pr123, the spectral weight of the chain contribution to the optical conductivity [9] as well as the ARPES spectra [16] are also consistent with an approximately quarter-filled conduction band. However, semiconducting behavior of the dc-resistivity, steep suppression of the optical conductivity below 0.1 eV and vanishing ARPES intensity near the Fermi level all indicate the existence of a charge gap. Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) experiments in Pr123 [17] revealed line broadening and anomalies in relaxation rates, which were ascribed to a charge ordering instability.Apparent absence of static charge order in Pr124 may be due to slight deviation from the quarter-filling [15] or to the geometrical frustration of intersite Coulomb interactions in zigzag chains [18]. However, dynamic signature towards charge order instability is indicated by the optical conductivity in Pr124, which splits into a zero-energy Drude part with a small weight and a finite energy mode centered at 40 meV [10]. In this letter, we report results of NQR experiments for the chain Cu sites in Pr124. We found a pronounced peak in the temperature dependences of the nuclear spin-lattice relaxation rate (1/T 1 ) and spin-echo decay rate (1/T 2 ), as well as broadening of the NQR spectra, indicating gradual freezing of fluctuations of electric field gradient (EFG) with decreasing temperature.The powder sample of Pr124 was synthesized by solid stat...

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supporting

confidence: 67%

Charge Freezing in the Zigzag ChainPrBa2Cu4O
Fujiyama
¹
,
Takigawa
²
,
Horii
³

2003
Phys. Rev. Lett.
31
3
25
0
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“…This has been interpreted as the "smearing" of the transition caused by the large impurity density 14,15,16 . Analogous behaviour is also seen in cuprate ladder compounds exhibiting sliding density waves 17,18 below T ≃200 K. As in the case of the cuprates, the resistivity of La 0.5 Ca 0.5 MnO 3 shows an activated temperature dependence with an activation energy which varies from ≃ 1000 − 1400 K (Figure 1b and c). Figure 2 shows the differential resistivity as a function of DC bias applied parallel (along the lattice vector a) and perpendicular to (along the lattice vector c) the superlattice direction.…”

mentioning

confidence: 49%

Sliding charge-density wave in manganites

et al. 2007

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The so-called stripe phase of the manganites is an important example of the complex behaviour of metal oxides, and has long been interpreted as the localisation of charge at atomic sites 1,2,3,4 . Here, we demonstrate via resistance measurements on La 0.50 Ca 0.50 MnO 3 that this state is in fact a prototypical charge density wave (CDW) which undergoes collective transport. Dramatic resistance hysteresis effects and broadband noise properties are observed, both of which are typical of sliding CDW systems. Moreover, the high levels of disorder typical of manganites result in behaviour similar to that of well-known disordered CDW materials. Our discovery that the manganite superstructure is a CDW shows that unusual transport and structural properties do not require exotic physics, but can emerge when a well-understood phase (the CDW) coexists with disorder.The stripe phase in manganites of the form La 1−x Ca x MnO 3 appears as the temperature is lowered through T ≃ 240 K, and the superstructure wavevector settles on a final value of q≃ (1 − x)a * 1 (where a * is the reciprocal lattice vector) for 0.5 ≤ x < 0.85, at T ≃ 120 K 2 . Based on the insulating nature of the manganites up to room temperature, and the observation of stripes of charge order in transmission electron microscopy (TEM) images, early studies concluded that the superstructure arose from localisation of charge at atomic sites 3,4 . However, neutron and xray studies found the degree of charge localisation at Mn sites to be small, and subsequent theoretical work suggested that a CDW model may be more applicable 5 . This suggestion is supported by the observation that q/a * is strongly temperature dependent 2,6 , indicating that a model in which the superstructure periodicity is derived from the sample stoichiometry cannot be valid. In addition, heat capacity peaks at the transition to the stripe phase can be modelled as "dirty Peierls transitions", expected in a disordered CDW system 7 . However, the possibility of the stripe phase exhibiting sliding behaviour, as seen in many other CDW systems 8 , could not be probed without the ability to make orientation-dependent resistivity measurements. Here we describe the first such measurements on the manganite stripe phase, which reveal dramatic

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“…On the other hand more recent NMR experiments are explained in terms of a transfer of holes from the ladders into the chains with decreasing temperature [6]. The insulating character indicates that the holes are localized at low temperatures and indeed a charge valence ordering below 200 K is claimed on the basis of results obtained by many different experimental techniques [7,8,9,10,11,12]. The existence of two different Cu sites in the chains has been shown by NMR measurements were two distinct resonances have been observed [7].…”

Section: Introductionmentioning

confidence: 98%

Structural modulations inSr14Cu24O41and their relation to charge ordering

et al. 2006

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Structural properties of the spin chain and ladder compound Sr14Cu24O41 have been studied using diffraction with hard x-rays. Strong incommensurate modulation reflections are observed due to the lattice mismatch of the chain and ladder structure, respectively. While modulation reflections of low orders display only a weak temperature independence, higher orders dramatically increase in intensity when cooling the sample to 10 K. All observed modulation reflections are indexed within the super space group symmetry and no structural phase transition could be identified between 10 K and room temperature. We argue that these modulation reflections are not caused by a five-fold periodicity of the chain lattice, as claimed by Fukuda et al. Phys. Rev. B 66, 012104 (2002), but that holes localize in the potential given by the lattice modulation, which in turn gives rise to a further deformation of the lattice.

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Sliding Density Wave in Sr ₁₄ Cu ₂₄ O ₄₁ Ladder Compounds

Abstract: We used transport and Raman scattering measurements to identify the insulating state of self-doped spin ½ two-leg ladders of Sr 14 Cu 24 O 41 as a weakly pinned, sliding density wave with nonlinear conductivity and a giant dielectric response that persists to remarkably high temperatures.

Cited by 111 publications

References 29 publications

Charge Freezing in the Zigzag ChainPrBa2Cu4O
Fujiyama
¹
,
Takigawa
²
,
Horii
³

2003
Phys. Rev. Lett.
31
3
25
0
View full text Add to dashboard Cite

Charge Freezing in the Zigzag ChainPrBa2Cu4O
Fujiyama
¹
,
Takigawa
²
,
Horii
³

2003
Phys. Rev. Lett.
31
3
25
0
View full text Add to dashboard Cite

Sliding charge-density wave in manganites

Structural modulations inSr14Cu24O41and their relation to charge ordering

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Sliding Density Wave in Sr 14 Cu 24 O 41 Ladder Compounds

Cited by 111 publications

References 29 publications

Charge Freezing in the Zigzag ChainPrBa2Cu4OFujiyama1, Takigawa2, Horii3 2003Phys. Rev. Lett.313250View full textAdd to dashboardCite

Charge Freezing in the Zigzag ChainPrBa2Cu4OFujiyama1, Takigawa2, Horii3 2003Phys. Rev. Lett.313250View full textAdd to dashboardCite

Sliding charge-density wave in manganites

Structural modulations inSr14Cu24O41and their relation to charge ordering

Contact Info

Product

Resources

About

Sliding Density Wave in Sr ₁₄ Cu ₂₄ O ₄₁ Ladder Compounds

Charge Freezing in the Zigzag ChainPrBa2Cu4O
Fujiyama
¹
,
Takigawa
²
,
Horii
³

2003
Phys. Rev. Lett.
31
3
25
0
View full text Add to dashboard Cite

Charge Freezing in the Zigzag ChainPrBa2Cu4O
Fujiyama
¹
,
Takigawa
²
,
Horii
³

2003
Phys. Rev. Lett.
31
3
25
0
View full text Add to dashboard Cite