  We prepared the samples K$_{1-x}$Ln$_{x}$Fe$_2$As$_2$ (Ln=Sm, Nd and La) with
ThCr$_2$Si$_2$-type structure. These samples were characterized by X-ray
diffraction, resistivity, susceptibility and thermoelectric power (TEP).
Substitution of Ln (Ln=La, Nd and Sm) for K in K$_{1-x}$Ln$_{x}$Fe$_2$As$_2$
system raises the superconducting transition temperature to 34-36 K. The TEP
measurements indicate that the TEP of K$_{1-x}$Ln$_{x}$Fe$_2$As$_2$ is
positive, being similar to the case of the Ba$_{1-x}$K$_{x}$Fe$_2$As$_2$ system
with p-type carrier. In the K$_{1-x}$Ln$_{x}$Fe$_2$As$_2$ system, the
superconducting $KFe_2As_2$ with $T_c\sim 3$ K is the parent compound, and no
structural and spin-density wave instabilities exist in this system.
