Ferroelectric functionality in SrTiO3/Si heterojunctions

Abstract

By the first-principles calculations, various SrTiO3/Si interface architectures have been studied in this work and the computed results showed that the stable ferroelectricity can be realized in the SrTiO3/Si system. The Si/SrO interface architecture with the Si-O configuration showed predominately the ferroelectric nature and the height of the potential barrier between the negative and positive poled states (0.77 eV per interfacial unit cell). The presence of the covalent bond between the substrate Si and O of SrO layer adjacent to the substrate Si leads to the disappearance of the electronic dipoles at the interface, and the reason is that the Si-O configuration of the Si/SrO interface architecture exhibits ferroelectric nature. In order to further understand the influence of the interfacial bonding nature on the ferroelectricity of the oxide layer, the BaTiO3/Si heterojunction with the same interface architectures also have been studied. Indeed, the Si/BaO interface architecture with the Si-O configuration showed predominately the ferroelectric nature too. Certainly, a full SrO (or BaO) layer directly grown on the substrate Si is benefit to the realization of the ferroelectric functionality in the ferroelectric-Si heterojunction. These findings are useful for the understanding of the basic physics of the ferroelectric-Si heterojunction and the silicon-based functional oxide device design.

Theoretical prediction of double perovskite Cs2AgxCu1-xInyTb1-yCl6 for infrared detection

“…The first-principles computations are performed applying the projector augmented plane-wave (PAW) method [25] and the generalized gradient approximation (GGA) of the Perdew-Burke-Ernzerhof (PBE) functional on the basis of DFT, through the Vienna Ab-Initio Simulation Package (VASP) [26][27][28]. Because of the underestimation by PBE, the Heyd-Scuseria-Ernzerhof (HSE06) is also applied to calculate the band gap and analyze the band edge [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. A plane-wave cutoff energy of 450 eV is employed and a 3 × 3 × 3 Monkhorst-Pack grid of reciprocal space integration is used for the mixed metal perovskite.…”

Modeling of Ferroelectric Oxide Perovskites: From First to Second Principles

“…A priori, the compressive epitaxial strain should make it ferroelectric, but it has been argued that the transfer of charge at the interface and related built-in dipole is pinning the polarization and preventing switching in the regime of thickness in which the film remains under epitaxial constraint (333,334). Still, this conclusion might depend on the structure of the interface, and ferroelectric switching might eventually be possible in the case of a less ionic interface (335).…”

Diffraction studies for stoichiometry effects in BaTiO3 grown by molecular beam epitaxy on Ge(001)

“…7 Since then, the epitaxy of STO onto Si substrates was heavily investigated, given its excellent compatibility with several other functional oxides and its interesting material characteristics. [8][9][10] Nevertheless, its properties are highly dependent on the exact epitaxial conditions such as substrates used, growth temperature, and, especially, stoichiometry. [11][12][13][14] Even if several techniques for realizing high quality STO thin film have been developed, [15][16][17] avoiding local or global non-stoichiometry is still difficult.…”