SET-based experiments for HTSC materials

Alam, Sher; Ōyanagi, H.; Rahman, M. O.; Yanagisawa, Takashi

doi:10.1088/0953-2048/15/9/310

Cited by 3 publications

(3 citation statements)

References 18 publications

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“…This inhomegeniety we suspect appears in the temperature dependent XANES spectra of Zn-doped LSCO samples [15]. In order to confirm the spincharge separation and 1-d behaviour we have also suggested SET based experiments for the HTSC and related materials [16]. It is interesting to note that a recent paper on pseudogap and quantum-transition phenomenology in HTSC cuprates by Tallon et al, [17] supports our suggestion that psuedogap may be related to short-range AF correlations.…”

Section: Experimental Support For Our Scenariomentioning

confidence: 86%

Quantum group based theory for antiferromagnetism and superconductivity: proof and further evidence

Alam

Mamun

Yanagisawa

et al. 2003

Physica C: Superconductivity

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Previously one of us presented a conjecture [APF-4 Proceedings] to model antiferromagnetism and high temperature superconductivity and their 'unification' by quantum group symmetry rather than the corresponding classical symmetry in view of the critique by Baskaran and Anderson of Zhang's classical SO(5) model. This conjecture was further sharpened, experimental evidence and the important role of 1-d systems [stripes] was emphasized and moreover the relationship between quantum groups and strings via WZWN models were given in [Phys. Lett A272, (2000)]. In this brief note we give and discuss mathematical proof of this conjecture, which completes an important part of this idea, since previously an explicit simple mathematical proof was lacking. Moreover an independent calculation [IC/99/2] which constructs the generators forming SO(5) algebra not only supports our previous conjecture but provides a check on our calculations. It is important to note that in terms of physics that the arbitariness [freedom] of the d-wave factor g 2 (k) is tied to quantum group symmetry whereas in order to recover classical SO(5) one must set it to unity in an adhoc manner. We intuitively expect that this freedom may be related to psuedogap behaviour in cuprates.

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Section: Experimental Support For Our Scenariomentioning

confidence: 86%

Quantum group based theory for antiferromagnetism and superconductivity: proof and further evidence

Alam

Mamun

Yanagisawa

et al. 2003

Physica C: Superconductivity

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“…In particular it seems that 3d-electron systems exhibit ordering and disordering of the fundamental degrees of freedom such as charge, spin and orbital. In turn it is plausible that this may be responsible for metal-insulator transition [3], high-T c superconductivity [1,4], and colossal magnetoresistance [5]. A class of materials which show charge-orbital ordering of e g electrons are the mixed valent manganites, the perovskite-type:…”

Section: Introductionmentioning

confidence: 99%

“…Recently Kawanaka [3] have prepared a single crystal of LaSrFeO 4 by floating-zone method and demonstrated a spin flop transition in the antiferromagnetic ground state.In particular it seems that 3d-electron systems exhibit ordering and disordering of the fundamental degrees of freedom such as charge, spin and orbital. In turn it is plausible that this may be responsible for metal-insulator transition[3], high-T c superconductivity [1,4], and colossal magnetoresistance [5]. A class of materials which show charge-orbital ordering of e g electrons are the mixed valent manganites, the perovskite-type:where RE=trivalent lanthanides, and AE=divalent alkaline-earth ions.…”

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confidence: 99%

Possible experimental signature of charge-orbital density waves inNd1−xCa1+xMnO4: Heat capacity and magnetization study

Alam¹,

Islam²,

Nagai³

et al. 2007

Phys. Rev. B

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Single Crystals of Nd 1−x Ca 1+x MnO 4 have been prepared by the traveling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In the current note we present direct evidence of charge-orbital ordering in this material using heat capacity measurements. Our heat capacity measurements indicate a clear transition consistent with prior observation. We find two main transitions, one at temperature T HC H = 310−314 K, and other in the vicinity of T HC A = 143 K. In addition, we may also conclude that there is a strong electron-phonon coupling in this material. In order to further study and confirm these anomalies we have performed dc magnetization measurements. The dc magnetic measurements confirm these two transitions. Again,we find two main transitions, one at temperature T M H = 318 − 323 K, and other at around T M A = 164 K. PACS numbers: 78.20.-e, 78.30.-j, 74.76.Bz 1 The transition-metal oxides display a wide variety of interesting properties. In particular of interest are the 3d transition metals such as Fe, Cu, Ni, Co and Mn, having a single layered perovskite structure, i.e. K 2 NiF 4 -type. These materials provide us useful insights into the underlying Mott-Hubbard in addition to helping us understand the superconducting oxides to which they are similar. In a recent note we [1] have shown the existence of inhomogenous charge distribution in very good quality single crystal of LaSrCuO 4 [LSCO] co-doped with 1% Zn at the copper site, using temperature dependent polarized X-ray absorption near-edge structure [XANES] spectra. A related single-layered compound to the LSCO is LaSrFeO 4 whose atomic and magnetic structure was first elucidated by Souberoux et al.[2], using X-ray diffraction, Mossbauer spectroscopy and neutron diffraction in polycrystalline state. Recently Kawanaka [3] have prepared a single crystal of LaSrFeO 4 by floating-zone method and demonstrated a spin flop transition in the antiferromagnetic ground state.In particular it seems that 3d-electron systems exhibit ordering and disordering of the fundamental degrees of freedom such as charge, spin and orbital. In turn it is plausible that this may be responsible for metal-insulator transition[3], high-T c superconductivity [1,4], and colossal magnetoresistance [5]. A class of materials which show charge-orbital ordering of e g electrons are the mixed valent manganites, the perovskite-type:where RE=trivalent lanthanides, and AE=divalent alkaline-earth ions. The real-space ordering pattern, possibly induced by strong electron-phonon interaction, that is a cooperative Jahn-Teller effect, can be determined by crystallographic superstructure [6,7]. What physical insight can be gained from these crystallographic superstructure? Here are some examples, for the case of the overdoped single-layered manganites, the suggested models [7,8] indicate that the Mn valence is not an integer but suffers a ...

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Quantum Groups, Strings and HTSC materials II

Alam¹,

Rahman²,

Yanagisawa³

et al. 2001

Preprint

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SET-based experiments for HTSC materials

Abstract: The cuprates seem to exhibit statistics, dimensionality and phase transitions in novel ways. The nature of excitations [i.e. quasiparticle or collective], spincharge separation, stripes [static and dynamics], inhomogeneities, psuedogap,

Cited by 3 publications

References 18 publications

Quantum group based theory for antiferromagnetism and superconductivity: proof and further evidence

Quantum group based theory for antiferromagnetism and superconductivity: proof and further evidence

Possible experimental signature of charge-orbital density waves inNd1−xCa1+xMnO4: Heat capacity and magnetization study

Quantum Groups, Strings and HTSC materials II

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