Stanene-hexagonal boron nitride heterobilayer: Structure and characterization of electronic property

Abstract

The structural and electronic properties of stanene/hexagonal boron nitride (Sn/h-BN) heterobilayer with different stacking patterns are studied using first principle calculations within the framework of density functional theory. The electronic band structure of different stacking patterns shows a direct band gap of ~30 meV at Dirac point and at the Fermi energy level with a Fermi velocity of ~0.53 × 106 ms−1. Linear Dirac dispersion relation is nearly preserved and the calculated small effective mass in the order of 0.05mo suggests high carrier mobility. Density of states and space charge distribution of the considered heterobilayer structure near the conduction and the valence bands show unsaturated π orbitals of stanene. This indicates that electronic carriers are expected to transport only through the stanene layer, thereby leaving the h-BN layer to be a good choice as a substrate for the heterostructure. We have also explored the modulation of the obtained band gap by changing the interlayer spacing between h-BN and Sn layer and by applying tensile biaxial strain to the heterostructure. A small increase in the band gap is observed with the increasing percentage of strain. Our results suggest that, Sn/h-BN heterostructure can be a potential candidate for Sn-based nanoelectronics and spintronic applications.

Structural and electronic properties of Stanene-BeO heterobilayer

“…The bandgap of pristine stanene without and with SOC is shown separately in figures 4(a) and (b) respectively. This result is found to be in a good agreement with 2D monolayer stanene studies of Modarresi et al [46] (70 meV bandgap in the presence of SOC), Xiong et al [47] (73 meV bandgap in the presence of SOC) as well as of Khan et al [24] (69 meV bandgap with SOC).…”

“…In this work, a two-atom hexagonal unit cell is considered for the buckled honeycomb structure of stanene. The optimized lattice constant and buckling height of pristine stanene is 4.66 Å and 0.84 Å respectively, which is in good agreement with already reported theoretical [17,18,24,[35][36][37] and experimental reports [13,14]. Bader charge analysis shows that each Sn atom contains the same number of electrons (3.99 |e|).…”

“…The sublattice symmetry of stanene monolayer, which shows zero bandgap without SOC, is broken with the introduction of BeO monolayer and the resulting interaction between them. A similar phenomenon of symmetry breaking and bandgap opening has been reported for heterostructures such as Germanene/BeO [38] Graphene/h-Bn [49], Stanene/h-Bn [24] and Stanene/MoS 2 [50].…”

“…Moreover, biaxial strains and an external electric field is applied to this heterostructure and is found to effectively tune the bandgap. Our results show that Sn/BeO heterostructure can be effectively made to harness the interesting properties of stanene, similar to Sn/h-BN [24] and Sn/ZnO [25].…”

“…Figure 3(c) shows an impressive bandgap opening of 98 meV for Sn/BeO heterostructure (without SOC) located at the K point after the introduction of the BeO substrate. The opened bandgap is larger than the bandgap of Sn/h-BN heterostructure [24]. The significant opened bandgap shows the possibility of improved on-off current ratio property, which can be harnessed in Sn/BeO made logical devices [45,48].…”