Abstract
We utilize first principles calculations to investigate the mechanical properties and strain-dependent electronic band structure of the hexagonal phase of two dimensional (2D) HfS2. We apply three different deformation modes within −10% to 30% range of two uniaxial (D1, D2) and one biaxial (D3) strains along x, y, and x-y directions, respectively. The harmonic regions are identified in each deformation mode. The ultimate stress for D1, D2, and D3 deformations is obtained as 0.037, 0.038 and 0.044 (eV/Ang3), respectively. Additionally, the ultimate strain for D1, D2, and D3 deformation is obtained as 17.2, 17.51, and 21.17 (eV/Ang3), respectively. In the next step, we determine the second-, third-, and fourth-order elastic constants and the electronic properties of both unstrained and strained HfS2 monolayers are investigated. Our findings reveal that the unstrained HfS2 monolayer is a semiconductor with an indirect bandgap of 1.12 eV. We then tune the bandgap of HfS2 with strain engineering. Our findings reveal how to tune and control the electronic properties of HfS2 monolayer with strain engineering, and make it a potential candidate for a wide range of applications including photovoltaics, electronics and optoelectronics.
Highlights
The rise of two-dimensional (2D) materials began in 2004 with a focus on graphene sheets by Novoselov and Geim [1]
Graphene is a 2D layer of sp2-bonded carbons as the first prototype of 2D layered materials, which is viewed as an ideal material for a wide range of applications including photonics, THz electronics, nonlinear optics, sensors, and transparent electrodes [2,3,4,5]. 2D materials have been intensively researched for the generation of ultrathin and flexible electronic and optoelectronic devices, including transistors, phototransistors, solar cells, and light-emitting diodes (LEDs) [6,7,8,9]
SItnraainll-Sthtrreeses Rdelfaotriomnashtiiopn modes, the total energy of the system increases with increasing the ammtopouptdchlhyeeFsishingeiisggubahsrylteemrrta3hoi(nesFsht.iegtoAqhuwuesresacstaat2ihmno).enebss.etoHrsafeoiecnwon-nesitvtnrieneFrsu,isgfuourmrerlDeatht23i,eodTonerhsfyoeorocbmfhtaaaeitnlniaogesnetdiscmfiortofoydEm. eAs,twsthhiecetahDrnasFtbteTreaocisfnaeelefcnonuerliranDgtyi1tohcanihnssadfanisDgguew2rwdeel,eiltfthaohsresmttsrhataeritenifosiitsnssstrain curves are depicted for all D1, D2, and D3 deformation modes
Summary
The rise of two-dimensional (2D) materials began in 2004 with a focus on graphene sheets by Novoselov and Geim [1]. 2D materials have been intensively researched for the generation of ultrathin and flexible electronic and optoelectronic devices, including transistors, phototransistors, solar cells, and light-emitting diodes (LEDs) [6,7,8,9]. These materials have historically been one of the most extensively studied classes of materials due to their wealth of significant physical phenomena, which can occur when charge and heat transports are confined to a 2D surface [10,11,12]. We do strain engineering to tune the electronic properties of the HfS2 monolayer and make it a potential candidate for different applications
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