Neutron scattering study of spin ordering and stripe pinning in superconducting La_1.93 Sr_0.07 CuO₄

TY - JOUR

T1 - Neutron scattering study of spin ordering and stripe pinning in superconducting La1.93 Sr0.07 CuO4

AU - Jacobsen, Henrik

AU - Zaliznyak, I.A.

AU - Savici, A.T.

AU - Winn, B.L.

AU - Chang, S.

AU - Hücker, M.

AU - Gu, G.D.

AU - Tranquada, J.M.

PY - 2015/11/20

Y1 - 2015/11/20

N2 - The relationships among charge order, spin fluctuations, and superconductivity in underdoped cuprates remain controversial. We use neutron scattering techniques to study these phenomena in La1.93Sr0.07CuO4, a superconductor with a transition temperature of Tc=20 K. At TTc we find incommensurate spin fluctuations with a quasielastic energy spectrum and no sign of a gap within the energy range from 0.2 to 15 meV. A weak elastic magnetic component grows below ∼10 K, consistent with results from local probes. Regarding the atomic lattice, we have discovered unexpectedly strong fluctuations of the CuO6 octahedra about Cu-O bonds, which are associated with inequivalent O sites within the CuO2 planes. Furthermore, we observed a weak elastic (33¯0) superlattice peak that implies a reduced lattice symmetry. The presence of inequivalent O sites rationalizes various pieces of evidence for charge stripe order in underdoped La2-xSrxCuO4. The coexistence of superconductivity with quasistatic spin-stripe order suggests the presence of intertwined orders; however, the rotation of the stripe orientation away from the Cu-O bonds might be connected with evidence for a finite gap at the nodal points of the superconducting gap function.

AB - The relationships among charge order, spin fluctuations, and superconductivity in underdoped cuprates remain controversial. We use neutron scattering techniques to study these phenomena in La1.93Sr0.07CuO4, a superconductor with a transition temperature of Tc=20 K. At TTc we find incommensurate spin fluctuations with a quasielastic energy spectrum and no sign of a gap within the energy range from 0.2 to 15 meV. A weak elastic magnetic component grows below ∼10 K, consistent with results from local probes. Regarding the atomic lattice, we have discovered unexpectedly strong fluctuations of the CuO6 octahedra about Cu-O bonds, which are associated with inequivalent O sites within the CuO2 planes. Furthermore, we observed a weak elastic (33¯0) superlattice peak that implies a reduced lattice symmetry. The presence of inequivalent O sites rationalizes various pieces of evidence for charge stripe order in underdoped La2-xSrxCuO4. The coexistence of superconductivity with quasistatic spin-stripe order suggests the presence of intertwined orders; however, the rotation of the stripe orientation away from the Cu-O bonds might be connected with evidence for a finite gap at the nodal points of the superconducting gap function.

U2 - 10.1103/physrevb.92.174525

DO - 10.1103/physrevb.92.174525

M3 - Journal article

SN - 2469-9950

VL - 92

JO - Physical Review B

JF - Physical Review B

M1 - 174525

ER -