Strain-dependent electronic and magnetic properties of MoS2 monolayer, bilayer, nanoribbons and nanotubes

Abstract

We investigate the strain-dependent electronic and magnetic properties of two-dimensional (2D) monolayer and bilayer MoS(2), as well as 1D MoS(2) nanoribbons and nanotubes using first-principles calculations. For 2D monolayer MoS(2) subjected to isotropic or uniaxial tensile strain, the direct band gap of MoS(2) changes to an indirect gap that decreases monotonically with increasing strain; while under the compressive strain, the original direct band gap is enlarged first, followed by gap reduction when the strain is beyond -2%. The effect of isotropic strain is even stronger than that of uniaxial strain. For bilayer MoS(2) subjected to isotropic tensile strain, its indirect gap reduces monotonically to zero at strain about 6%; while under the isotropic compressive strain, its indirect gap increases first and then reduces and turns into direct gap when the strain is beyond -4%. For strained 1D metallic zigzag MoS(2) nanoribbons, the net magnetic moment increases slightly with axial strain from about -5% to 5%, but drops to zero when the compressive strain is beyond -5% or increases with a power law beyond 5%. For 1D armchair MoS(2) nanotubes, tensile or compressive axial strain reduces or enlarges the band gap linearly, and the gap can be fully closed for nanotubes with relatively small diameter or under large tensile strain. For zigzag MoS(2) nanotubes, the strain effect becomes nonlinear and the tensile strain can reduce the band gap, whereas compressive strain can initially enlarge the band gap and then decrease it. The strain induced change in projected orbitals energy of Mo and the coupling between the Mo atom d orbital and the S atom p orbital are analyzed to explain the strong strain effect on the band gap and magnetic properties.

First-principles study of strain-induced charge polarization in a molybdenum disulfide monolayer

“…Figure 3(a) shows the band gap evolution of MoS 2 monolayer versus the intensity value of strain. In particular, one can observe that the band gap decreases upon the tensile symmetrical strain; ultimately, the MoS 2 single-layer exhibits the metallic behavior under the tensile biaxial strain " = 12%, whereas the compressive biaxial strain of " = 2% at rst causes the band gap to increase; but, the increase in the compressive strain causes the band gap to decrease, of which the trend is in agreement with the theoretically reported works [16,17]. Figure 3(b) and (c) shows the charge evolution of S and Mo atoms upon three types of strain, which is estimated using the Mulliken population analysis.…”

“…The electronic properties of MoS 2 monolayer can be manipulated by means of applying strain [13][14][15][16][17][18] and external electric and magnetic elds [19]. For example, the biaxial planar tensile strain induces direct to indirect band gap transition in MoS 2 monolayer [13,15].…”

Transition Metal‐Promoted V2CO2 (MXenes): A New and Highly Active Catalyst for Hydrogen Evolution Reaction

“…Strain engineering has been proved to be an efficient way to tune the physical and chemical properties of 2D materials, including MXenes,29, 30, 31 which may have influence on the HER performance as well. Moreover, the real HER experiments are generally very complicated.…”

Electron transport in MoWSeS monolayers in the presence of an external electric field

“…For example, by applying a small mechanical strain of about 1% to the MoS 2 monolayer, the band gap shifts from direct to indirect, and for larger deformations a semiconductor-metal transition occurs. [12][13][14][15][16] By means of further theoretical studies it has been reported that applying an external electric field to a rippled MoS 2 monolayer 17 or an armchair MoS 2 nanoribbon 18 reduces the band gap and causes severe changes in the electronic structure. Ramasubramaniam and co-workers 19 have studied the effect of the perpendicular external electric field applied to TX 2 bilayers.…”