Neutron Scattering Evidence for a Periodically-Modulated Superconducting Phase in the Underdoped Cuprate La$_{1.905}$Ba$_{0.095}$CuO$_4$

摘要

The role of antiferromagnetic spin correlations in high-temperaturesuperconductors remains a matter of debate. We present inelastic neutronscattering evidence that gapless spin fluctuations coexist withsuperconductivity in La$_{1.905}$Ba$_{0.095}$CuO$_4$. Furthermore, we observethat both the low-energy magnetic spectral weight and the spinincommensurability are enhanced by the onset of superconducting correlations.We propose that the coexistence occurs through intertwining of spatialmodulations of the pair wave function and the antiferromagnetic correlations.This proposal is also directly relevant to sufficiently underdopedLa$_{2-x}$Sr$_x$CuO$_4$ and YBa$_2$Cu$_3$O$_{6+x}$.