Static magnetic order on the metallic triangular lattice inCrSe2detected byμSR+

Abstract

The magnetic nature of a metallic two-dimensional triangular compound, ${\mathrm{CrSe}}_{2}$, has been investigated by muon spin rotation and relaxation ($\ensuremath{\mu}^{+}\mathrm{SR}$) measurements using both powder and single crystal samples. It is found that ${\mathrm{CrSe}}_{2}$ enters into a static antiferromagnetic (AF) ordered state below 157 K ($={T}_{\mathrm{N}}$). Furthermore, the AF state is slightly changed below around 20 K ($={T}_{\mathrm{N}2}$). Based on the analysis of the internal magnetic fields at the muon sites predicted with DFT calculations, collinear AF and helical ${120}^{\ensuremath{\circ}}$ AF are clearly eliminated for the ground state of ${\mathrm{CrSe}}_{2}$. The most probable one is an incommensurate spin density wave order.