TY - JOUR
T1 - Pseudo Gap Formation Studied by B2u Phonon Measurements
AU - Harashina, Hiroshi
AU - Sasaki, Hisashi
AU - Kodama, Katsuaki
AU - Sato, Masatoshi
AU - Shamoto, Shin Ichi
AU - Kakurai, Kazuhisa
AU - Nishi, Masakazu
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1998/9
Y1 - 1998/9
N2 - Neutron scattering studies on a c-axis polarized B2u phonon have been carried out by using single crystals of YBa2Cu3O7, YBa2Cu3O6.7 and YBa2Cu2.9Zn0.1O6.75. For YBa2Cu3O7, sharp decreases in the energy and width of the phonon mode have been observed with decreasing temperature T at around the superconducting transition temperature Tc. For the underdoped samples, the gradual downward deviations of these quantities from the ordinary T-dependence begin far above Tc with decreasing T, which is considered to be associated with the formation of the pseudo gap with the same symmetry as that of the superconducting order parameter, i.e., the (x2-y2)-like one. These deviations become significant, with decreasing T, at temperatures higher than the so-called spin-gap temperature TSG of YBa2Cu3O6.7 (∼150 K). Observed insensitive nature of the anomaly above Tc to the Zn-doping can be explained by considering the wave vector (q) dependence of the pseudo gap and the coupling strength of the B2u mode to the gap, and also by considering that randomness effects introduced by the doping are more significant in the q-region with the smaller energy gap.
AB - Neutron scattering studies on a c-axis polarized B2u phonon have been carried out by using single crystals of YBa2Cu3O7, YBa2Cu3O6.7 and YBa2Cu2.9Zn0.1O6.75. For YBa2Cu3O7, sharp decreases in the energy and width of the phonon mode have been observed with decreasing temperature T at around the superconducting transition temperature Tc. For the underdoped samples, the gradual downward deviations of these quantities from the ordinary T-dependence begin far above Tc with decreasing T, which is considered to be associated with the formation of the pseudo gap with the same symmetry as that of the superconducting order parameter, i.e., the (x2-y2)-like one. These deviations become significant, with decreasing T, at temperatures higher than the so-called spin-gap temperature TSG of YBa2Cu3O6.7 (∼150 K). Observed insensitive nature of the anomaly above Tc to the Zn-doping can be explained by considering the wave vector (q) dependence of the pseudo gap and the coupling strength of the B2u mode to the gap, and also by considering that randomness effects introduced by the doping are more significant in the q-region with the smaller energy gap.
UR - http://www.scopus.com/inward/record.url?scp=0032257447&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032257447&partnerID=8YFLogxK
U2 - 10.1143/JPSJ.67.3216
DO - 10.1143/JPSJ.67.3216
M3 - Article
AN - SCOPUS:0032257447
VL - 67
SP - 3216
EP - 3223
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 9
ER -