Dynamic surface modification due to effusion of Na in Na₂IrO₃

The honeycomb lattice iridate Na₂IrO₃ shows frustrated magnetism and can potentially display Kitaev-like exchange interactions. It has been recognized as a promising playground for studying various strongly correlated phenomena. Owing to its potential for showing novel ground states driven by the interplay of spin orbit coupling and strong electron correlations, it has drawn considerable attention of the condensed matter community and inspired a great deal of theoretical and experimental efforts. Na₂IrO₃ has a layered honeycomb structure and under certain conditions, it has also been proposed to be a topological insulator, a material with a bulk band gap and topologically protected conducting surface states thereby becoming a possible candidate to show quantum spin Hall (QSH) effect at relatively higher temperatures. Recently, it was shown that the electronic properties of the surface of crystalline Na₂IrO₃ can be tuned by Argon (Ar) plasma treatment in a controlled manner leading to various phases of matter ranging from a fully gapped to a metallic surface, where the possibility of a charge-density wave (CDW) like transition has been suggested. Detailed investigation of the physical, chemical and electronic properties of the surface of high quality Na₂IrO₃ crystals using scanning probe microscopy (SPM) in various modes has been carried out