  We examine the effect of the magnetic frustration J' on the single-hole
spectral function in the t-t'-t''-J model. At zero temperature, the exact
diagonalization (ED) and the self-consistent Born approximation (SCBA) methods
are used. We find that the frustration suppresses the quasiparticle (QP) weight
at small momentum k, whereas the QP peak at k=(pi/2,pi/2) remains sharp. We
also show the temperature dependence of the single-hole spectral function by
using the ED method. It is found that the lineshapes at (pi/2,0) and
(pi/2,pi/2) show different temperature dependence. These findings are
consistent with the angle-resolved photoemission data on Sr2CuO2Cl2, and
indicate the importance of the magnetic frustration on the electronic states of
the insulating cuprates.
