918 research outputs found
All-Solution-Processed InGaO 3
We fabricated the crystallized InGaZnO thin films by sol-gel process and high-temperature annealing at 900°C. Prior to the deposition of the InGaZnO, ZnO buffer layers were also coated by sol-gel process, which was followed by thermal annealing. After the synthesis and annealing of the InGaZnO, the InGaZnO thin film on the ZnO buffer layer with preferred orientation showed periodic diffraction patterns in the X-ray diffraction, resulting in a superlattice structure. This film consisted of nanosized grains with two phases of InGaO3(ZnO)1 and InGaO3(ZnO)2 in InGaZnO polycrystal. On the other hand, the use of no ZnO buffer layer and randomly oriented ZnO buffer induced the absence of the InGaZnO crystal related patterns. This indicated that the ZnO buffer with high c-axis preferred orientation reduced the critical temperature for the crystallization of the layered InGaZnO. The InGaZnO thin films formed with nanosized grains of two-phase InGaO3(ZnO)m superlattice showed considerably low thermal conductivity (1.14 Wm−1 K−1 at 325 K) due to the phonon scattering from grain boundaries as well as interfaces in the superlattice grain
Competing Magnetic Orderings and Tunable Topological States in Two-Dimensional Hexagonal Organometallic Lattices
The exploration of topological states is of significant fundamental and
practical importance in contemporary condensed matter physics, for which the
extension to two-dimensional (2D) organometallic systems is particularly
attractive. Using first-principles calculations, we show that a 2D hexagonal
triphenyl-lead lattice composed of only main group elements is susceptible to a
magnetic instability, characterized by a considerably more stable
antiferromagnetic (AFM) insulating state rather than the topologically
nontrivial quantum spin Hall state proposed recently. Even though this AFM
phase is topologically trivial, it possesses an intricate emergent degree of
freedom, defined by the product of spin and valley indices, leading to Berry
curvature-induced spin and valley currents under electron or hole doping.
Furthermore, such a trivial band insulator can be tuned into a topologically
nontrivial matter by the application of an out-of-plane electric field, which
destroys the AFM order, favoring instead ferrimagnetic spin ordering and a
quantum anomalous Hall state with a non-zero topological invariant. These
findings further enrich our understanding of 2D hexagonal organometallic
lattices for potential applications in spintronics and valleytronics.Comment: 9 pages, 8 figure
- …