Controllable Growth of α- and β-Antimonene by Interfacial Strain

Abstract

Antimonene has two different allotropes, namely, orthorhombic α-Sb and rhombohedral β-Sb. Both phases exhibit unique electronic properties and have been prepared on various substrates. However, the controllable growth of α- and β-Sb has remained challenging. In the present work, we demonstrate that α- and β-Sb can be controllably grown on a family of inert substrates with hexagonal structures. The preferential phase of antimonene can be tuned through the interfacial strain induced by the lattice mismatch. Our work clarifies the mechanism for the controllable growth of α- and β-Sb on various substrates, shedding light on the synthesis of 2D Xenes suitable for practical applications.

Structures of α-BixSb1–x Alloys Formed on the TiSe2 Substrates

“…The line profile (Figure 1g) of the as-grown α-Sb along the red line marked in Figure 1e reveals an interlayer spacing of 0.7 ± 0.01 nm, in accordance with the monolayer height of α-Sb on TiSe 2 . 1 Atomic-resolution STM image (Figure 1f) unravels a rectangular unit cell with a = 4.61 ± 0.10 Å and b = 4.14 ± 0.10 Å, akin to that on the TiSe 2 substrates. 1,10 By adjustment of the flux ratio and deposition sequence of Bi and Sb, a series of α-Bi x Sb 1−x alloys with similar orthorhombic lattice structures can be obtained.…”

“…1 Atomic-resolution STM image (Figure 1f) unravels a rectangular unit cell with a = 4.61 ± 0.10 Å and b = 4.14 ± 0.10 Å, akin to that on the TiSe 2 substrates. 1,10 By adjustment of the flux ratio and deposition sequence of Bi and Sb, a series of α-Bi x Sb 1−x alloys with similar orthorhombic lattice structures can be obtained. Indeed, we find that the compositions of α-Bi x Sb 1−x alloys do not depend on the intuitional growth parameters, but are attributed to the local stoichiometry, in contrast to previous work in which uniform monolayer Bi−Sb alloys were formed on GeSe substrates with Bi−Sb codeposition at a 420 K sample temperature.…”

“…Among the emerging Xenes, Bismuthene and antimonene belong to the same group-VA and have two allotropes with orthorhombic (α-phase) and rhombohedral (β-phase) structures. 1 As Bi and Sb atoms are rather heavy, the strong spin−orbit coupling (SOC) results in a variety of intriguing topological properties. For instance, Reis and co-workers prepared β-Bi with a honeycomb lattice on the SiC(0001) substrates and detected a wide gap up to ∼0.8 eV in bulk and topological conductive edge states, demonstrating the great potential of β-Bi for the realization of quantum spin Hall effect at room temperature (RT).…”

“…14 Recently, we reported the controllable growth of α-Sb on the TiSe 2 substrates and β-Sb on the Bi 2 Se 3 and Sb 2 Te 3 substrates, as well as the coexistence of both phases on the HfTe 2 substrates. 1 Notably, Hogan et al found that α-Sb grown on Bi 2 Se 3 can undergo a phase transition to β-Sb by sample annealing. 15 As Bi and Sb possess similar 2D crystal structures and physical properties, their alloys also exhibit rich physical properties, by adjusting stoichiometry.…”

Realizing a Superconducting Square-Lattice Bismuth Monolayer

“…Low-dimensional systems with various symmetries under strong spin–orbit coupling (SOC) have been widely investigated to achieve exotic electronic and spintronic properties and functionalities including topological properties, helical spin textures, and Dirac fermions. − These research activities have been extended to artificial two-dimensional (2D) heterostructures by combining materials of strong SOC with those of superconducting and ferromagnetic properties, which provide a route to Majorana quasiparticles and innovative quantum devices . In particular, elemental 2D materials composed of heavy group 15 elements (As, Sb, Bi) have been highlighted because of their strong SOC and the existence of various 2D allotropes such as α, β, γ, and ζ forms. − Different types of allotropes were obtained on different substrates − and further controlled through annealing and changing thickness , based on subtle energetics of different allotropes, which provides wide phase space for physics and a high degree of freedom in material design for devices. A prototype example is monolayers of bismuth with the strongest SOC.…”