paper

Pressure-induced formation of rhodium zigzag chains in the honeycomb rhodate Li $_{2}$ RhO $_{3}$

arXiv:1905.04930 · doi:10.1103/PhysRevB.100.064105

Abstract

We use powder x-ray diffraction to study the effect of pressure on the crystal structure of the honeycomb rhodate Li $_{2}$ RhO $_{3}$ . We observe low-pressure ( $P$ $<$ $P_{c 1}$ = 6.5 GPa) and high-pressure ( $P$ $>$ $P_{c 2}$ = 14 GPa) regions corresponding to the monoclinic $C 2/ m$ symmetry, while a phase mixture is observed at intermediate pressures. At $P$ $>$ $P_{c 2}$ , the honeycomb structure becomes distorted and features short Rh--Rh bonds forming zigzag chains stretched along the crystallographic $a$ direction. This is in contrast to dimerized patterns observed in triclinic high-pressure polymorphs of $I^\pm$ -Li $_{2}$ IrO $_{3}$ and $I^\pm$ -RuCl $_{3}$ . Density-functional theory calculations at various pressure conditions reveal that the observed rhodium zigzag-chain pattern is not expected under hydrostatic pressure but can be reproduced by assuming anisotropic pressure conditions.

11 pages, 11 figures

Pressure-induced formation of rhodium zigzag chains in the honeycomb rhodate Li2​RhO3​

Abstract

Pressure-induced formation of rhodium zigzag chains in the honeycomb rhodate Li $_{2}$ RhO $_{3}$