Abstract:
On the basis of a two-orbital model (including
and
orbitals), we perform a systematic study of the superconducting property in single-layered La
2−x(Sr/Ba)
xCuO
4 and HgBa
2CuO
4+x by using the constrained-path Monte Carlo method. We find that the d-wave pairing correlation is strongly enhanced with increasing the energy difference ΔE between and orbitals, which provides a reasonable explanation of higher superconducting critical temperature Tc in HgBa
2CuO
4+x than in La
2−x(Sr/Ba)
xCuO
4. The similar spin correlations in the La- and Hg-based systems suggest that antiferromagnetism is not responsible for material-dependent superconductivity. Further analysis indicates that the hole density
on the orbital increases with increasing ΔE, leading to a higher Tc in the Hg-based system with larger ΔE. Our results are useful for understanding the superconducting property in single-layered high-Tc cuprates.