Magneto-optical absorption in silicene and germanene induced by electric and Zeeman fields

Abstract

We study the optical absorption properties of silicene and germanene in the presence of the perpendicular magnetic and electric fields. Their low-energy Landau level (LL) spectra are controllable by an external electric field, where the spin-and valley-degeneracy of the LLs are strongly influenced by the electric and Zeeman fields. The electric field has removed spin-degeneracy at a given valley. Analytical expressions for the magneto-optical absorption coefficient (MOAC) are expressed in the presence of the interaction between carriers and random impurities and the intrinsic phonons including the spin and valley effects. The results evaluated for the topological insulator and valley-spin-polarized metal phases showed that when the electric field is included, the MOAC peaks are separated for opposite spin cases where the splitting in germanene is stronger than that in silicene. The peak's intensity caused by the carrier-photon-impurity scattering is the highest, the next is the carrier-photon scattering, while the carrier-photon-phonon scattering shows the lowest in both materials. Among the different phonon modes, the out-of-plane (ZA) mode in silicene dominates the others, being attributed to its buckled atomic structure, which does not exist in graphene. When the ZA mode is taken into account, the estimated resultant mobility from the full-width at half-maximum is significantly supported by the experimental result in silicene.

Electronic, optical, and thermoelectric properties of Janus In-based monochalcogenides

“…Many 2D layered structures have been explored and joined the 2D family, including silicene [5], germanene [6], transition metal dichalcogenides (TMDs) [7], and monochalcogenides [8]. Besides, a series of theoretical studies on this material family has been performed by using different approaches [9][10][11][12][13][14][15]. Among them, monolayers of the group III monochalcogenides, which have been experimentally synthesized [16][17][18][19], emerged as nanomaterials with great prospect for applications in high-performance water-splitting and optoelectronic devices [20,21].…”

Computational insights into structural, electronic, and optical properties of Janus GeSO monolayer

“…1,2 Aer the discovery of graphene in 2004, 3 a series of other 2D materials have been intensively studied by both the theoretical and experimental methods. 4,5 2D structures of silicene, phosphorene, h-boron nitride, germanane, or transitional metal dichalcogenides (TMDs) have been predicted to be promising candidates for next-generation electronic devices. [6][7][8][9][10] Janus 2D structure has recently emerged as a novel 2D material which has received widespread attention.…”

New C2h phase of group III monochalcogenide monolayers AlX (X = S, Se, and Te) with anisotropic crystal structure: first-principles study

“…Since the invention of graphene in 2004, 1 intense research in the eld of two-dimensional (2D) nanostructures has been carried out by both theoretical and experimental studies. [2][3][4][5] 2D layered-structures, such as silicene, 6 germanene, 2 or metal chalcogenide compounds 7 possess many novel physical features that cannot be found in their bulk phases. Among those interesting candidates, group III-VI post-transition metal chalcogenides have appeared recently as a promising family due to their intriguing physical properties.…”