Magnetic-field-induced spin excitations and renormalized spin gap of the underdoped La1.895Sr0.105CuO4 superconductor.
High-resolution neutron inelastic scattering experiments in applied magnetic fields have been performed on La1.895Sr0.105CuO4 (LSCO). In zero field, the temperature dependence of the low-energy peak intensity at the incommensurate momentum transfer QIC=(0.5,0.5+/-delta,0),(0.5+/-delta,0.5,0) exhibits an anomaly at the superconducting Tc which broadens and shifts to lower temperature upon the application of a magnetic field along the c axis. A field-induced enhancement of the spectral weight is observed, but only at finite energy transfers and in an intermediate temperature range. These observations establish the opening of a strongly downward renormalized spin gap in the underdoped regime of LSCO. This behavior contrasts with the observed doping dependence of most electronic energy features.
Chang
J
J
Laboratory for Neutron Scattering, ETH Zurich and PSI Villigen, CH-5232 Villigen PSI, Switzerland.
Schnyder
A P
AP
Gilardi
R
R
Rønnow
H M
HM
Pailhes
S
S
Christensen
N B
NB
Niedermayer
Ch
Ch
McMorrow
D F
DF
Hiess
A
A
Stunault
A
A
Enderle
M
M
Lake
B
B
Sobolev
O
O
Momono
N
N
Oda
M
M
Ido
M
M
Mudry
C
C
Mesot
J
J