Strain-tunable band parameters of ZnO monolayer in graphene-like honeycomb structure

Abstract

We present ab initio calculations which show that the direct-band-gap, effective masses and Fermi velocities of charge carriers in ZnO monolayer (ML-ZnO) in graphene-like honeycomb structure are all tunable by application of in-plane homogeneous biaxial strain. Within our simulated strain limit of ±10%, the band gap remains direct and shows a strong non-linear variation with strain. Moreover, the average Fermi velocity of electrons in unstrained ML-ZnO is of the same order of magnitude as that in graphene. The results promise potential applications of ML-ZnO in mechatronics/straintronics and other nano-devices such as the nano-electromechanical systems (NEMS) and nano-optomechanical systems (NOMS).

Tailoring the structural and electronic properties of a graphene-like ZnS monolayer using biaxial strain

“…Our calculated LDA band gap of 2.622 eV is larger than the reported GGA value of E g = 2.07 eV for ZnS single sheet [9]. For the purpose of comparison with ML-ZnO, we would like to note that the band gap of ML-ZnS is larger than the reported GGA value [27] of E g = 1.68 eV for ML-ZnO, which is identical with our calculated LDA value for ML-ZnO [17]. This clearly suggests that ML-ZnS will be useful in device applications where materials with higher band gap than that of ML-ZnO is required.…”

“…The calculations have been performed by using the DFT based full-potential (linearized) augmented plane wave plus local orbital (FP-(L)APW+lo) method [10] as implemented in the elk-code [11]. We use the Perdew-Zunger variant of LDA [12], the accuracy of which has been successfully tested in our previous studies [13][14][15][16][17][18][19][20][21] of graphene and some graphene-like 2D crystals. For instance, our LDA value of the Fermi velocity in graphene, viz., 8.327 × 10 5 m/s [21], matches well with that calculated using the WIEN2k code, viz., 8.2 × 10 5 m/s (LAPW+LDA) [22] and 8.33 × 10 5 m/s (LAPW+GGA) [23].…”

Strain-engineered band parameters of graphene-like SiC monolayer

“…We have used the Elk-code [23] and the Perdew-Zunger variant of local density approximation (LDA) [24] for our calculations, the accuracy of which has been tested in our previous works of other 2D crystals [9,10,[25][26][27][28]. The k-point grid size of 20 20 1 was used for structural and of 30 30 1 was used for band structure calculations using the Monkhorst-Pack scheme [29].…”

Graphene and some of its structural analogues: full-potential density functional theory calculations

“…We use the DFT based full-potential (linearized) augmented plane wave plus local orbital (FP-(L)APW+lo) method [27][28][29] as implemented in the elk-code (http:// elk.sourceforge.net/) and the Perdew-Zunger [30] variant of local density approximation (LDA) for our calculations. The accuracy of this method and code has been successfully tested in our previous studies [31][32][33][34][35][36][37]. For plane wave expansion in the interstitial region, we have used 8 ≤ |G + k| max × R mt ≤ 9, where R mt is the smallest muffin-tin radius, for deciding the plane wave cut-off.…”