Nonlocal protons and deuterons opposed to disorder: a single-crystal neutron diffraction study of KH0.76D0.24CO3 and a theoretical framewok

François Fillaux (1) , Alain Cousson (2)

1 LADIR - Laboratoire de Dynamique Interactions et Réactivité
2 LLB - UMR 12 - Laboratoire Léon Brillouin

We show with neutron diffraction that a single-crystal of potassium hydrogen deuterium carbonate at room temperature, namely KH$_{0.76}$D$_{0.24}$CO$_3$, is isomorphous with the KHCO$_3$ and KDCO$_3$ derivatives. Protons and deuterons are not disordered particles located at definite sites and Bragg peaks are best fitted with separate H and D sublattices. We propose a theoretical framework for nonlocal observables and macroscopic states compatible with the crystal field.

Domaines: Autre [cond-mat.other]; Physique Quantique [quant-ph]

François Fillaux, Alain Cousson. Nonlocal protons and deuterons opposed to disorder: a single-crystal neutron diffraction study of KH0.76D0.24CO3 and a theoretical framewok. Journal of Physics: Condensed Matter, 2008, 20, pp.252202. ⟨10.1088/0953-8984/02/25/252202⟩. ⟨hal-00293987⟩