TY - JOUR
T1 - Laser-excited ultrahigh-resolution photoemission spectroscopy of Na xCoO 2·yH 2O
T2 - Evidence for pseudogap formation
AU - Shimojima, T.
AU - Yokoya, T.
AU - Kiss, T.
AU - Chainani, A.
AU - Shin, S.
AU - Togashi, T.
AU - Watanabe, S.
AU - Zhang, C.
AU - Chen, C. T.
AU - Takada, K.
AU - Sasaki, T.
AU - Sakurai, H.
AU - Takayama-Muromachi, E.
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2005/1
Y1 - 2005/1
N2 - We have studied the temperature (T)-dependent electronic structure near the Fermi level of the layered cobaltate superconductor, Na 0.35CoO 2·1.3H 2O, and related materials, using laser-excited ultrahigh-resolution photoemission spectroscopy. We observe the formation of a pseudogap (PG) with an energy scale of ∼20 meV in Na 0.35CoO 2·1.3H 2O and Na 0.35CoO 2·0.7H 2O, which is clearly absent in Na 0.7CoO 2. The energy scale of the PG is larger than the expected value for the superconducting gap, suggesting an additional competing order parameter at low T. We discuss implications of the PG in relation to available transport and magnetic susceptibility results.
AB - We have studied the temperature (T)-dependent electronic structure near the Fermi level of the layered cobaltate superconductor, Na 0.35CoO 2·1.3H 2O, and related materials, using laser-excited ultrahigh-resolution photoemission spectroscopy. We observe the formation of a pseudogap (PG) with an energy scale of ∼20 meV in Na 0.35CoO 2·1.3H 2O and Na 0.35CoO 2·0.7H 2O, which is clearly absent in Na 0.7CoO 2. The energy scale of the PG is larger than the expected value for the superconducting gap, suggesting an additional competing order parameter at low T. We discuss implications of the PG in relation to available transport and magnetic susceptibility results.
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U2 - 10.1103/PhysRevB.71.020505
DO - 10.1103/PhysRevB.71.020505
M3 - Article
AN - SCOPUS:20144387669
VL - 71
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 2
M1 - 020505
ER -