Electronic and optical properties of silicene under uni-axial and bi-axial mechanical strains: A first principle study

Tuned electronic, optical and mechanical properties of pristine and hetero nanotubes of group IV elements (C, Si and Ge)

“…Strain dependent band structure: The strain is defined as (e¼ a a / 0 Δ ) [64] and the strained unit cell is modelled by applying tensile as well as compression strains by varying the lattice value 'a' with strain 'e'. Here a 0 is an equilibrium lattice constant and a Δ is the change in lattice constant simulating the strain.…”

Dirac points and van Hove singularities of silicene under uniaxial strain

“…In contrast, several previous studies predicted that silicene stretched uniaxially can become a semiconductor with a small band gap. 29,30 This may be due to the coarse k-points in the previous calculations of band structures, which is also the reason for some incorrect description of low energy electronic structures of graphene under uniaxial strain. 25 Under AC strain, one DP (D 1 ) is located in the K-S 1 (K 1 -S) line, and the other DP (D 2 ), which is the inversion of D 1 , lies in the R-S line.…”

“…[26][27][28][29][30] Detailed analysis is thus performed above by carefully calculating the DOS to get the energies of VHSs as well as the band structures around the M, S, or S 1 points to identify the saddle points of these bands, which are the origin of the VHSs. In previous studies, the transitions of silicene into metal under large strain are observed and analysed in details, and the transitions are due to the overlapping of the DPs with the r* band around the C point under biaxial strain and AC strain, or along the S-C line under the ZZ strain.…”

“…In previous studies, the transitions of silicene into metal under large strain are observed and analysed in details, and the transitions are due to the overlapping of the DPs with the r* band around the C point under biaxial strain and AC strain, or along the S-C line under the ZZ strain. [26][27][28][29][30] However, no identification of the M or S 1 point as the saddle points of the r* bands has been made in previous studies of silicene under uniaxial strain. 29,30 Then, comparison between the VHSs of the p* and r* bands has not been able to be made before.…”

“…24 In contrast to graphene, both the r* and p* bands of silicene are sensitive to the tensile strain. [26][27][28][29][30] First-principles calculations show that silicene becomes metallic under biaxial strain larger than about 10%. [26][27][28] Under uniaxial strain, silicene turns into a metal under AC strain and ZZ strain larger than 10% and 12%, respectively.…”