Relation between weak-wide pseudo gap effect and spin fluctuations in electron doped cuprate Pr$_{1-x}$LaCe$_{x}$CuO$_{4}$

Magnetic behavior of electron doped cuprate Pr$_{1-x}$LaCe$_{x}$CuO$_{4}$(PLCCO) is different from that of typical electron doped cuprates such as Nd$_{2-x}$Ce$_{x}$CuO$_{4}$(NCCO). Its long range anti-ferromagnetic (AFM) order disappears at a lower Ce concentration than NCCO, and spin fluctuations as well as superconductivity exist over a wide doping range. It is therefore interesting to study in detail electronic structure of PLCCO and its spin correlations. We performed angle resolved photoemission spectroscopy studies on PLCCO(x=0.09, 0.12, 0.15) to investigate the doping dependent electronic structures. Different from other electron doped cuprates, nodal bands cross the Fermi level, even for x=0.09 doped samples. That is, the hole pocket near ($\pi $/2,$\pi $/2) region survives for doping as low as x=0.09. Yet, the pseudo gap (PG) is well defined for x=0.09 and is gradually suppressed as the doping increases to x=0.15. This behavior can be attributed to coupling of electrons to a weaker AF phase fluctuation which implies a weak PG effect over a wider doping range. This is consistent with earlier neutron scattering result.