Spectral function of the charge-density-wave (CDW) phonon in an anisotropic CDW superconductor

1984 ◽  
Vol 30 (11) ◽  
pp. 6387-6396 ◽  
Author(s):  
X. L. Lei ◽  
C. S. Ting ◽  
Joseph L. Birman
Keyword(s):  
Charge Density ◽  
Spectral Function ◽  
Charge Density Wave ◽  
Density Wave

scholarly journals Unitarity bound violation in holography and the instability toward the charge density wave

2020 ◽  
Vol 35 (22) ◽  
pp. 2050128
Author(s):  
Geunho Song ◽  
Yunseok Seo ◽  
Sang-Jin Sin
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Fermi Surface ◽  
Charge Density ◽  
Spectral Function ◽  
Charge Density Wave ◽  
Density Wave ◽  
Surface Phenomena ◽  
Unitarity Bound ◽  
Conformal Field

We study the spectral function of holographic fermions with Pauli term. We find the [Formula: see text]-dependent instability signaled by the tachyonic spectrum ([Formula: see text]-gap) from the [Formula: see text] regime where unitarity is violated. We suggest that this is the instability toward the charge density wave (CDW) based on the similarity of the unitarity violation in conformal field theory (CFT) and the nesting Fermi surface phenomena in weakly interaction system: both of them give divergent enhancement of degree of freedom.

Dispersion of superconducting gap excitations in layered charge density wave systems

1983 ◽  
Vol 61 (8) ◽  
pp. 1160-1168 ◽  
Author(s):  
G. C. Mahanty ◽  
S. N. Behera
Keyword(s):  
Charge Density ◽  
Spectral Function ◽  
Charge Density Wave ◽  
Energy Gap ◽  
Density Wave ◽  
Exact Expression ◽  
Experimental Result ◽  
Layered Compound ◽  
Present Calculation ◽  
Peak Structure

The phonon spectral function for charge density wave (CDW) systems in the superconducting (SC) phase is calculated for finite wave vectors (q). An exact expression for the q dependent phonon self-energy is obtained. The analysis is carried out with a small q limit. The spectral function shows a two peak structure for frequencies co less than the SC energy gap (2Δ) in contrast to the single peak obtained by Balseiro and Falicov for q = 0. The peaks approach each other with increasing q and finally merge into one. Both modes have linear dispersions for small q and the frequency of the low-lying one goes to zero as q → 0. For ω > 2Δ the phonon spectrum does not change significantly. The results are discussed in context with the Raman scattering observation of SC gap excitations in 2H–NbSc2 (a layered compound exhibiting both CDW and SC transitions) by Sooryakumar and Klein. The present calculation demands that the strength of coupling between the CDW phonon and SC electrons be an order of magnitude smaller than that used for q = 0 in order to get an agreement with the experimental result.

Incommensurate modulated phases of the NbxTa1-xTe4 charge density wave system

1992 ◽  
Vol 50 (1) ◽  
pp. 58-59
Author(s):  
S. Ritchie ◽  
J. C. Bennett ◽  
A. Prodan ◽  
F.W. Boswell ◽  
J.M. Corbett
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Direct Evidence ◽  
Density Wave ◽  
Wave System ◽  
Modulated Phases ◽  
Metal Atoms ◽  
Incommensurate Modulation ◽  
End Members ◽  
Modulation Wave Vector

A continuous sequence of compounds having composition NbxTa1-xTe4; 0 ≤ x ≤ 1 have been studied by electron diffraction and microscopy. Previous studies have shown that the end members of the series, TaTε4 and NbTε4 possess a quasi-one-dimensional character and exhibit charge density wave (CDW) distortions. In these compounds, the subcell structure is tetragonal with axes (a × a × c) and consists of the metal atoms (Nb or Ta) centered within an extended antiprismatic cage of Te atoms. At room temperature, TaTε4 has a commensurate modulation structure with a 2a × 2a × 3c unit cell. In NbTε4, an incommensurate modulation with × ∼ 16c axes is observed. Preliminary studies of the mixed compounds NbxTα1-xTε4 showed a discontinuous jump of the modulation wave vector commensurate to incommensurate when the Nb dopant concentration x, exceeded x ≃ 0.3, In this paper, the nature of the compositional dependence of is studied in greater detail and evidence is presented for a stepwise variation of . This constitutes the first direct evidence for a Devil's staircase in CDW materials.

Wave Analysis of the Charge Density Wave Dynamics in the Molecular Conductor (Perylene)2Pt(mnt)2 (mnt=maleonitriledithiolate)

1995 ◽  
Vol 5 (5) ◽  
pp. 539-545 ◽  
Author(s):  
J. Dumas ◽  
N. Thirion ◽  
M. Almeida ◽  
E. B. Lopes ◽  
M. J. Matos ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Analysis ◽  
Wave Dynamics ◽  
Molecular Conductor

Tunneling spectroscopy in the Charge-Density Wave conductor NbSe3

2004 ◽  
Vol 114 ◽  
pp. 135-136 ◽  
Author(s):  
E. Slot ◽  
K. O'Neill ◽  
H. S.J. van der Zant ◽  
R. E. Thorne
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Tunneling Spectroscopy
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