Interaction of Adatoms and Molecules with Single-Layer Arsenene Phases

Abstract

Recent studies have shown that arsenic can form single-layer phases in buckled honeycomb as well as symmetric washboard structures, named as arsenene. These structures are stable even in freestanding form and are nonmagnetic semiconductors in the energy range which is suitable for various electronic applications. In this study we investigated the adsorption of selected adatoms (H, Li, B, C, N, O, Al, Si, P, Cl, Ti, Ga, Ge, As, Se and Sb) and physisorption of molecules (H 2 , O 2 and H 2 O) to these two arsene phases. Since the interaction of these adspecies with arsenene are studied using large supercells, the coupling between adspecies is minimized, and hence our results can be interpreted to mimic the effects of isolated adatom or physisorbed molecule. It is found that the adatoms form strong chemisorption bonds and hence modify the atomic structure and physical properties locally. Some of the adatoms give rise to significant local reconstruction of the atomic structure. Electronic states of some adatoms become spin polarized and attain net magnetic moments; they may even display half-metallic character at high coverage. Majority of adsorbed atoms give rise to localized states in the fundamental band gap. We showed that the interactions between H 2 , O 2 and H 2 O molecules and single-layer arsenene are rather weak and do not cause any significant changes in the physical properties of these molecules, as well as those of arsenene phases. However, some of these molecules can be dissociated at the edges of the flakes of arsenene structures; their constituents are adsorbed to the edge atoms and cause to local reconstructions.

Stable single-layer structure of group-V elements

“…After the synthesis of very thin films of phosphorus [27] researchers started to seek similar structures in other group-V elements or pnictogens. Recent theoretical studies have predicted that nitrogen [28], phosphorus [29][30][31], arsenic [32][33][34][35], antimony [36][37][38][39], bismuth [40][41][42][43], and compounds of group-V elements [44] can form stable freestanding SL, planar as well as buckled honeycomb (b) structures similar to that of silicene and germanene and also other manifolds, such as SL symmetric (w) and asymmetric (aw) washboard structures, among others. These SL phases are named, respectively, nitrogene, phosphorene, arsenene, antimonene, and bismuthene.…”

“…Earlier, we studied SL pnictogen phases consisting of planar and buckled honeycomb and symmetric and asymmetric washboard structures, whereby their dynamical and thermal stability, mechanical, electronic, magnetic, and optical properties were revealed and also their functionalization with selected single atoms and molecules was investigated [21,[34][35][36]43]. In those studies crucial effects of the structures on physical properties were revealed.…”

Stability of single-layer and multilayer arsenene and their mechanical and electronic properties

“…They also showed that these structures are stable against the long-wavelength displacements indicating the stability at T = 0 K. The predicted semiconducting character having a band gap in the range of 1.5-2.10 eV and other properties of arsenene have attracted considerable interest. Very recently, various theoretical studies contributed for better understanding of arsenene [10][11][12][13][14][15][16]. Promising progress towards the synthesis of these phases has also been reported [17].…”

Optical properties of single-layer and bilayer arsenene phases

“…Diverse allotropes of arsenene have been studied more with a focus on their structural, mechanical, and electronic properties, where arsenene and antimonene were also found to display high carrier mobility, superior mechanical properties, negative Poisson's ratio, and possible topological phase transition features in themselves [19][20][21][22][23][24][25][26][27]. The layered three-dimensional (3D) phase of arsenic, i.e., gray arsenic, presents strong evidence that single-layer arsenic can exist as a local minima in the Born-Oppenheimer surface.…”