=1/2 quantum antiferromagnet*

Here we present a neutron scattering study on a spin-1/2 two-leg ladder antiferromagnet C₉D₁₈N₂CuBr₄ (DLCB for short) under applied hydrostatic pressure. In DLCB, the inter-ladder coupling is sufficiently strong to drive the system to the Néel antiferromagnetic ordering phase below T_N=2 K and the analysis of the spin Hamiltonian reveals that DLCB is close to the quantum critical point in two dimensions at zero field and ambient pressure [1]. Single-crystal neutron diffraction measurements under pressures up to 1.3 Gpa suggest that size of the staggered moment becomes suppressed with increase of pressure and the magnetic order breaks down above pressure ~1.0 Gpa.

References:
[1] T. Hong et al., Phys. Rev. B 89, 174432 (2014); Nat. Phys. 13, 638 (2017).