Single-layer crystalline phases of antimony: Antimonenes

Abstract

The pseudolayered character of 3D bulk crystals of antimony has led us to predict its 2D single-layer crystalline phase named antimonene in a buckled honeycomb structure like silicene. Sb atoms also form an asymmetric washboard structure like black phospherene. Based on an extensive analysis comprising ab initio phonon and finite-temperature molecular dynamics calculations, we show that these two single-layer phases are robust and can remain stable at high temperatures. They are nonmagnetic semiconductors with band gaps ranging from 0.3 eV to 1.5 eV, and are suitable for 2D electronic applications. The washboard antimonene displays strongly directional mechanical properties, which may give rise to a strong influence of strain on the electronic properties. Single-layer antimonene phases form bilayer and trilayer structures with wide interlayer spacings. In multilayers, this spacing is reduced and eventually the structure changes to 3D pseudolayered bulk crystals. The zigzag and armchair nanoribbons of the antimonene phases have fundamental band gaps derived from reconstructed edge states and display a diversity of magnetic and electronic properties depending on their width and edge geometry. Their band gaps are tunable with the widths of the nanoribbons. When grown on substrates, such as germanene or Ge(111), the buckled antimonene attains a significant influence of substrates.

Optical properties of single-layer and bilayer arsenene phases

“…The layered black and blue phosphorus with band gaps suitable for 2D electronics have initiated the search for similar structures in other group V elements or pnictogens. In general, the recent theoretical works have predicted that nitrogen [13], phosphorus [14], arsenic [15], antimony [16,17], and bismuth [18] can form similar single-layer, buckled honeycomb or washboard structures.…”

Effects of adatoms and physisorbed molecules on the physical properties of antimonene

“…Additionally, the armchair and zigzag nanoribbons of these single-layer structures have band gaps, which vary with the width of the ribbon. It was also found that the bilayer, as well as the overlayer of antimonene grown on a substrate, is metallized due to the interlayer coupling [1]. While this situation appears to limit the applicability of Bu-Sb and aW-Sb, the undesired interlayer coupling is weakened or lifted by the intercalation molecules as pillars.…”

“…Both ab initio calculations of phonon frequencies and high-temperature molecular dynamics calculations [1] have demonstrated that these two phases remain stable. While the SL buckled antimonene phase, Bu-Sb, is a semiconductor with a direct band gap of 1.04 eV calculated by using PBE (1.45 eV calculated by HSE correction [30]), aW-Sb has a relatively small direct band gap of 0.16 eV calculated by using PBE (0.34 eV after HSE correction [30]) [1]. Accordingly these two SL structures have band gaps suitable for various electronic applications.…”

“…In Sec. III, we present a brief summary on the properties of SL antimonene phases predicted in our previous study [1]. This way one can contrast the modified properties of adatoms adsorbed to antimonene phases with those of bare ones.…”

“…Our recent theoretical study [1] has shown that antimony (Sb) can form two different, single-layer (SL) 2D crystalline structures like silicene [2][3][4][5] and black phosphorene [6]. These are a buckled honeycomb structure (buckled, Bu antimonene or Bu-Sb) and an asymmetric washboard structure (aW antimonene or aW-Sb).…”