Study of Dion-Jacobson Phase Perovskite Ca2Nan-3NbnO3n+1- (n = 4 5 6) Nanosheets as Solar Water-Splitting Cells and Spintronic-computing Applications

Abstract

A well-crystalline two-dimensional (2-D) perovskite material Ca2Nan-3NbnO3n+1- (CNNO) nanosheets derived from the Dion-Jacobson phase has the potential to generate hydrogen through photoelectrochemical water splitting and become the prominent candidate for future spintronic devices Here we have successfully fabricated CNNO nanosheets with the different molecular thickness of n = 4 5 and 6 We investigate not only the feasibility of CNNO nanosheets to be used in solar water-splitting cells but also spintronic-based applications such as spintronic water splitting and skyrmion computing using coherent circularly ?/-? polarization light A skyrmion is a quasiparticle with the topologically stable spin swirls to hold the state of the spin electrons with a potential application as carrier information and holds promises for realizing the next-generation spintronic devices The magnetic skyrmion can be generated at room temperature and the mechanism comes from two reasons one is Dzyaloshinskii–Moriya interaction (DMI) happened because of the symmetry breaking of spin-orbit coupling (SOC) and another one is double exchange mechanism that comes from the presence of two valence state of Nb4+ and Nb5+ in CNNO nanosheets The CNNO4 nanosheets exhibit weak ferromagnetic while CNNO5 and CNNO6 nanosheets exhibit superparamagnetic The magnetic skyrmion can be clearly observed in those 2D nanosheets without the application of the external magnetic field Using first-principles calculation and micromagnetic simulation the magnetic skyrmion in CNNO nanosheets shows N?el-type skyrmion with a diameter of 11-15 nm which is corresponding to the experimental results The spin electron hold in the topological state of magnetic skyrmion causes reduction reaction of hydrogen gas Our findings provide insights toward developing room-temperature skyrmion in CNNO nanosheets for future energy generation devices

Date of Award	2020
Original language	English
Supervisor	Yen-Hsun Su (Supervisor)