Intrachain collinear magnetism and interchain magnetic phases in Cr3As3- K -based materials

We perform a comparative study of the K⁢Cr3⁢As3 and the K2⁢Cr3⁢As3 quasi-one-dimensional compounds and show that the strong interplay between the lattice and the spin degrees of freedom promotes a collinear ferrimagnetic ground state within the chains in the presence of intrachain antiferromagnetic couplings. We propose that the interchain antiferromagnetic coupling in K⁢Cr3⁢As3 plays a crucial role in the experimentally observed spin-glass phase with low critical temperature. In the same region of the parameter space, we predict K2⁢Cr3⁢As3 to be nonmagnetic but on the verge of magnetism, sustaining interchain ferromagnetic spin fluctuations while the intrachain spin fluctuations are antiferromagnetic.