Electric- and magnetic-field dependence of the electronic and optical properties of phosphorene quantum dots

Abstract

Recently, black phosphorus quantum dots were fabricated experimentally. Motivated by these experiments, we theoretically investigate the electronic and optical properties of rectangular phosphorene quantum dots (RPQDs) in the presence of an in-plane electric field and a perpendicular magnetic field. The energy spectra and wave functions of RPQDs are obtained numerically using the tight-binding approach. We find edge states within the band gap of the RPQD which are well separated from the bulk states. In an undoped RPQD and for in-plane polarized light, due to the presence of well-defined edge states, we find three types of optical transitions which are between the bulk states, between the edge and bulk states, and between the edge states. The electric and magnetic fields influence the bulk-to-bulk, edge-to-bulk, and edge-to-edge transitions differently due to the different responses of bulk and edge states to these fields.

Aharonov-Bohm oscillations in phosphorene quantum rings

“…The TB model based on Eq. (1) has been applied previously to phosphorene nanoribbons [38] and PQDs [33,35]. Here, we extend it to PQRs in the presence of external fields and potentials.…”

“…Most recently, nanometer-sized phosphorene quantum dots (PQDs) have been fabricated and characterized [31,32]. This motivated theoretical studies of the electronic and optical properties of PQDs [33][34][35]. Some interesting results were obtained, such as unconventional edge states in PQDs [33,35] and anomalous size-dependent optical properties of PQDs [34].…”

“…This motivated theoretical studies of the electronic and optical properties of PQDs [33][34][35]. Some interesting results were obtained, such as unconventional edge states in PQDs [33,35] and anomalous size-dependent optical properties of PQDs [34]. Since a PQR can be viewed as a PQD containing an antidot, which introduces inner edges to the system, one can expect that the geometry of the ring and, depending on its width, the interedge coupling will lead to new physical properties which are not present in a PQD.…”

“…Previously, we investigated the electric and magnetic field dependence of the electronic and optical properties of PQDs by means of the tight-binding (TB) approach [35]. In the present paper, we will extend this approach to PQRs and study how the ring width, an in-plane electric field, and a side-gating potential influence the energy spectrum and the wave functions of a PQR.…”

Electro-optical properties of phosphorene quantum dots

“…The on-site energies are taken to be zero; h i = 0. This effective tight-binding model has been widely adopted to carry out systematic studies on monolayer phosphorene nanoribbons [62][63][64] and phosphorene quantum dots [27,28]. Applying a static electric field to the considered system adds the following potential to the on-site energy:…”