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A large number of compounds which contain BiS$_{2}$ layers exhibit enhanced superconductivity upon electron doping. Much interest and research effort has been focused on BiS$_{2}$-based compounds which provide new opportunities for exploring the nature of superconductivity. Important to the study of BiS$_{2}$-based superconductors is the relation between structure and superconductivity. By modifying either the superconducting BiS$_2$ layers or the blocking layers in these layered compounds, one can effectively tune the lattice parameters, local atomic environment, electronic structure, and other physical properties of these materials. In this article, we will review some of the recent progress on research of the effects of chemical substitution in BiS$_{2}$-based compounds, with special attention given to the compounds in the $Ln$OBiS$_{2}$ ($Ln$ = La-Nd) system. Strategies which are reported to be essential in optimizing superconductivity of these materials will also be discussed.
The upper critical field $H_{c2}$ of polycrystalline samples of $Ln$O$_{0.5}$F$_{0.5}$BiS$_{2}$ ($Ln$ = La, Nd) at ambient pressure (tetragonal structure) and high pressure (HP) (monoclinic structure) have been investigated via electrical resistivity
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,
We have synthesized a series of the Ruddlesden-Popper nickelate solid solution Ln4-xLnxNi3O10 (Ln and Ln = La, Pr and Nd; x = 0, 1, 2 and 3) via the citrate precursor method at different reacting atmospheres. Both the electronic-transport and magneti
Electrical resistivity measurements as a function of temperature between 1 K and 300 K were performed at various pressures up to 3 GPa on the superconducting layered compounds Ln(O0.5F0.5)BiS2 (Ln = La, Ce). At atmospheric pressure, La(O0.5F0.5)BiS2
Layered textit{Ln}OBiS$_2$ compounds with textit{Ln} = La, Ce, Pr, Nd, and Yb can be rendered conducting and superconducting via two routes, substitution of F for O or the tetravalent ions Ti, Zr, Hf, and Th for trivalent textit{Ln} ions. Electrical