LaSrVO4: A candidate for the spin-orbital liquid state

A layered perovskite LaSrVO4 was studied by neutron diffraction, pair distribution function measurement using synchrotron x-ray, susceptibility, and specific heat measurements, and first-principles calculation. The results show (i) a weak structural distortion around 100 K with the existence of orbital fluctuations both above and below it; (ii) the absence of the long range magnetic ordering down to 0.35 K but the appearance of a short range magnetic ordering around 11 K with a T-2 behavior of the specific heat below it. Meanwhile, the calculation based on the density functional theory predicts a magnetic ordered ground state. All facts indicate a melting of the magnetic ordering due to the orbital fluctuations in LaSrVO4, which makes it a rare candidate for the spin-orbital liquid state related to t(2g) orbitals.