Evidence of Coherent C-Axis Charge Transport in Underdoped La2-xSrxCuO4 Superconductors

Abstract

We have observed the plasma edge in the normal state c-axis far-infrared (far-IR) reflectivity of La2-xSrxCuO4 (LSCO) single crystals at an unlikely Sr-doping concentration x = 0.07 but not in x = 0.09. We find that the c-axis scattering rate (Gc) is surprisingly small, Gc = 13 (+_) 2 cm-1 for x = 0.07 and Gc = 24 (+_) 1 cm-1 for x = 0.09 and nearly temperature independent but increases linearly with doping up to x = 0.16. We suggest that the apparent absence of the normal state plasma edge in the previous measurements is due to the larger Gc than the screened plasma frequency of the coherent free carriers. We conclude that the c-axis charge transport in LSCO in the underdoped regime is intrinsically coherent.

arXiv comment4 pages, 4 figures. to appear in PRB71

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• Wigner Lattice Order, Collective Mode, and Superconductivity in La1.985Sr0.015CuO4+delta System
• Under-doped La2-xSrxCuO4 with x = 0.063 - 0.125: TSFZ growth of high-quality crystals and anomalous doping dependences of superconducting properties
• The composite picture of the charge carriers in La2-xSrxCuO4 (0.063 < x < 0.11) superconductors

Cited by in corpus (5)

• The impact of dynamical screening on the phonon dynamics of LaCuO
• Robust intrinsic electronic superconducting phases in underdoped La_{2-x}Sr_xCuO4 single crystals
• The "Bohr" Model for the High Tc Superconductivity
• Implications of Charge Ordering in the High Tc Cuprate Superconductors in the Far-infrared Spectroscopy
• In-plane and Out-of-plane Plasma Resonances in Optimally Doped La1.84Sr0.16CuO4