Normal-state Nernst effect in electron-doped Pr 2 − x Ce x Cu O 4 − δ </…
2007; American Physical Society; Volume: 76; Issue: 17 Linguagem: Inglês
10.1103/physrevb.76.174512
ISSN1550-235X
Autores Tópico(s)Magnetic and transport properties of perovskites and related materials
ResumoWe report a systematic study of the normal-state Nernst effect in the electron-doped cuprates ${\mathrm{Pr}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}\mathrm{Cu}{\mathrm{O}}_{4\ensuremath{-}\ensuremath{\delta}}$ over a wide range of doping $(0.05\ensuremath{\leqslant}x\ensuremath{\leqslant}0.21)$ and temperature. At low temperatures, we observed a notable vortex Nernst signal above ${T}_{c}$ in the underdoped films, but no such normal-state vortex Nernst signal is found in the overdoped region. The superconducting fluctuations in the underdoped region are most likely incoherent phase fluctuations as found in hole-doped cuprates. At high temperatures, a large normal-state Nernst signal is found at dopings from slightly underdoped to highly overdoped. Combined with normal-state thermoelectric power, Hall effect, and magnetoresistance measurements, the large Nernst effect is compatible with the two-band model. For the highly overdoped films, the large Nernst effect is anomalous and not explainable with the simple holelike Fermi surface seen in photoemission experiments.
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