T-Phase and H-Phase Coupled TMD van der Waals Heterostructure ZrS₂/MoTe₂ with Both Rashba Spin Splitting and Type-III Band Alignment

Abstract

Based on first-principles calculations, we systematically explored the electronic structures of the ZrS 2 /MoTe 2 heterostructure. The results show that Rashba splitting and type-III band alignment coexist in this heterostructure system. The presence of Rashba spin splitting makes this system of interest for spin-field-effect transistor applications. The effects of biaxial strain and an applied electric field on the electronic structure of a heterostructure were also explored. In the strain range of −2 to 6%, the system keeps the structural stability, and the electronic structure maintains the type-III band alignment. In particular, a crucial change from a type-III to a type-II band alignment occurred under the negative electric field of −0.4 to −0.6 V/Å, which can be beneficial to design multi-purpose devices. The current work predicts that the ZrS 2 /MoTe 2 heterostructure is an excellent candidate for the realization of multiple band arrangement conversion and tunnel-field-effect transistors, which deserves further experimental research.

Electric Field and Strain Tuning of 2D Semiconductor van der Waals Heterostructures for Tunnel Field-Effect Transistors

“…Notably, the interlayer distances should be predicted as accurately as possible to ensure a proper description of the orbital hybridization, electron charge transfer, electronic structure, etc. A recent paper reports 1H-MoTe 2 /1T-ZrS 2 heterobilayers having our the so-called vdWH-IV stacking pattern and an interlayer distance of 2.75 Å, which is slightly lower compared to our computed values using various van der Waals functionals.…”

Tuning the Electronic Properties of Two-Dimensional Lepidocrocite Titanium Dioxide-Based Heterojunctions

“…The interlayer distance between the monolayers was 2.75 Å in the TiO 2 /MoSSe and 2.90 Å in the TiO 2 /MoSeS. These values fall within the optimal range of vdW interaction, as discussed by Wang et al and Pushkarev et al The smaller interlayer distance in the TiO 2 /MoSSe may be attributed to a larger covalent radius of the Se atoms than the S atoms, resulting in a larger spacing between the monolayers. , Interlayer distances smaller than 3 Å have also been reported in previous investigations on TiO 2 -based heterostructures ,, and other vdW heterostructures as well. − To estimate the stability of the heterostructures, we calculated the formation energies using the equation E F = E normalH normale normalt normale normalr normalo normals normalt normalr normalu normalc normalt normalu normalr normale − E T i O 2 − E normalM normalo normalS normalS normale , where E Heterostructure is the total energy of the heterostructure, and E TiO 2 and E MoSSe are the total energies of the TiO 2 and MoSSe monolayers, respectively. The calculated formation energies of −5.52 and −5.50 eV for TiO 2 /MoSSe and TiO 2 /MoSeS, respectively, indicated that the vdW heterostructures are energetically favorable.…”

“… 51 , 52 Interlayer distances smaller than 3 Å have also been reported in previous investigations on TiO 2 -based heterostructures 28 , 29 , 53 and other vdW heterostructures as well. 54 − 56 To estimate the stability of the heterostructures, we calculated the formation energies using the equation where E Heterostructure is the total energy of the heterostructure, and E TiO 2 and E MoSSe are the total energies of the TiO 2 and MoSSe monolayers, respectively. The calculated formation energies of −5.52 and −5.50 eV for TiO 2 /MoSSe and TiO 2 /MoSeS, respectively, indicated that the vdW heterostructures are energetically favorable.…”

Emerging trends in 2D TMDs with a broken gap interface

“…The results show that Rashba splitting, and type-III band alignment coexist in this heterostructure system, making it suitable for spin-FET applications. 57 The electronic properties of the WTe 2 /HfS 2 vdW heterostructure can be effectively modulated by an external electric field and strain, and first-principles evidence showed that it has the long-sought type-III band alignment with a broken gap, offering a promising platform for the development of tunnel FETs. 58 However, in these heterostructures, experimental proof was necessary to observe the precise phenomenon.…”