Multiple charge density wave states and magnetism in NdPt2Si2 against the background of its nonmagnetic analog LaPt2Si2

Abstract

Results of structural, magnetic, thermodynamic, and electron transport measurements on single-crystalline ${\mathrm{NdPt}}_{2}{\mathrm{Si}}_{2}$ are reported. Temperature variations of crystal structure show two different charge density wave states. The structure modulation with the propagation vector ${\mathbit{q}}_{\mathbf{1}}=(0.323,0,0)$ arises below $T=300$ K. An additional modulation, with propagation vector ${\mathbit{q}}_{\mathbf{2}}=(0.163,0.163,0.500)$, appears below $T=50$ K in a first-order phase transition. This situation was found analogous to isostructural ${\mathrm{LaPt}}_{2}{\mathrm{Si}}_{2}$ with similar (but not identical) propagation vectors and characteristic temperatures. Nd magnetic moments order antiferromagnetically at ${T}_{N}=1.5$ K. Temperature dependence of electrical resistivity for current j applied along the $a$, $b$, and $c$ axes is strongly affected by the first-order transition, inducing a Fermi surface gapping.