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Unconventional inner-TL electric polarization in TL-LaOBiS2 with ultrahigh carrier mobility
Ist Teil von
Nanoscale, 2019-10, Vol.11 (39), p.18436-18443
Ort / Verlag
Cambridge: Royal Society of Chemistry
Erscheinungsjahr
2019
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Based on first principles calculations, we propose a new 2D ferroelectric material, triple-layer (TL) LaOBiS2, with an ultrahigh carrier mobility over 40 000 cm2 V−1 s−1 and large sunlight absorption. TL-LaOBiS2 is composed of a middle LaO layer and top-and-bottom BiS2 layers that can be possibly exfoliated from its bulk counterpart. We reveal that each BiS2 layer can hold spontaneous in-plane ferroelectric polarization that can be further enhanced by imposing extensive strain. Furthermore, we discover that TL-LaOBiS2 possesses unconventional inner-TL ferroelectric (FE), antiferroelectric (AFE) and orthogonal polarizations. The ground inner-TL AFE state can be flexibly driven into a nearly degenerate FE state. Moreover, the direct band gaps, optical absorption and the carrier mobilities of TL-LaOBiS2 can be effectively regulated by different ferroelectric polarization configurations. This finding of various ferroelectric states with ultrahigh mobility and excellent optical absorption in TL-LaOBiS2 provides a promising platform for future realization of two-dimensional ferroelectric photovoltaic devices.