2 research outputs found
Fundamental Properties of Hydrogen-Functionalized GaSe Monolayer
Functionalization reveals potential opportunities for
modifying
essential properties and designing materials due to the strong interaction
between functionalized atoms and the surface. Among them, hydrogenation
possesses such a way to control electronic and optical characteristics.
In this paper, the stability and transformed electronic, optical properties
of H-functionalized GaSe in two cases (single and double sites) were
reported that exhibit the effects of hydrogen functionalization via
first-principles calculations. Formation energies suggest that H-functionalized
GaSe systems are stable for construction. H-GaSe and 2H-GaSe display
distinct properties based on the functionalized way (single- or double-site
functionalization). Accordingly, H-GaSe is metallic, while 2H-GaSe
belongs to a semiconductor. The magnetic configuration with ferro-
and anti-ferromagnetic could be found in H- and 2H-functionalized
cases through spin distribution, respectively. Especially, the chemical
hybridized bonds of Se–H, Ga–Se, and Ga–Ga corresponding
to s-sp3 and sp3-sp3 bondings, respectively,
are clearly verified in the orbital-projected density of states and
charge density. The optical properties of 2H-GaSe could provide the
main characteristics of a semiconductor, which is the limited range
of transparency by electronic absorption at short and long wavelengths.
Moreover, increasing the number of GaSe segments (L) could change the band gap leading to application in the band gap
engineering of the 2H-GaSe systems. Thus, hydrogen functionalization
could provide the possible manner for adjusting and controlling features
of GaSe, promising for the development of electronic devices and applications
Configuration-Induced Rich Electronic Properties of Bilayer Graphene
The
objective of this paper is to investigate the geometric and electronic
properties of shift-dependent bilayer graphene along armchair and
zigzag directions using first-principle calculations. The interlayer
distance and the total ground state energy gradually decrease and
subsequently increase during the stacking configuration sequence:
AA → AB → AA′ → AA. Furthermore, there
are dramatic changes in which Dirac cones are transformed into parabolic
bands or nonvertical Dirac cones, accompanied by a separation of the
Dirac cones, creation of an arc-shaped stateless region, distorted
energy dispersions, extra low-energy critical points, and splitting
of middle-energy states. The density of states (DOS) exhibits many
prominent peaks derived from saddle points. All the bilayer systems
remain semimetals, with their free carrier densities strongly depending
on the stacking configuration. The main features of energy bands and
DOS can be used to identify the subangstrom misalignment stackings