Magnetic-field-induced soft-mode quantum phase transition in the high-temperature superconductor La1.855Sr0.145CuO4: an inelastic neutron-scattering study.
Inelastic neutron-scattering experiments on the high-temperature superconductor La1.855Sr0.145CuO4 reveal a magnetic excitation gap Delta that decreases continuously upon application of a magnetic field perpendicular to the CuO2 planes. The gap vanishes at the critical field required to induce long-range incommensurate antiferromagnetic order, providing compelling evidence for a field-induced soft-mode driven quantum phase transition.
Chang
J
J
Laboratory for Neutron Scattering, ETH Zurich and PSI Villigen, CH-5232 Villigen PSI, Switzerland. jchang@physique.usherbrooke.ca
Christensen
N B
NB
Niedermayer
Ch
Ch
Lefmann
K
K
Rønnow
H M
HM
McMorrow
D F
DF
Schneidewind
A
A
Link
P
P
Hiess
A
A
Boehm
M
M
Mottl
R
R
Pailhés
S
S
Momono
N
N
Oda
M
M
Ido
M
M
Mesot
J
J