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Alloys between Ga2O3 and Al2O3 (AGO) present a rich material space exhibiting numerous structural phases with unique optoelectronic properties that make them attractive candidates as ultra-wide bandgap (UWBG) semiconductors for next-generation power devices. Here we review the properties of AGO, focusing on theoretical results on the thermodynamics of Al incorporation and its consequences on the electronic structure. We review predictions and progress in experimentally realizing these alloys, as well as how composition influences important optoelectronic variables such as the band gap, band offsets, transport properties, and n-type dopability. A number of these parameters, such as the breakdown field (related to the band gap) and electron mobility, are discussed in assessing AGO in terms of relevant power device figures of merit. Overall, the rapid progress and predicted properties highlight the promise of AGO as a model UWBG semiconductor platform with the potential to revolutionize power devices.

Materials combining strong ferromagnetism and good semiconducting properties are highly desirable for spintronic applications (e.g., in spin-filtering devices). In this work, we conduct a search for concentrated ferromagnetic semiconductors through high-throughput computational screening. Our screening reveals the limited availability of semiconductors combining ferromagnetism and a low effective mass. We identify the manganese pyrochlore oxide In2Mn2O7 as especially promising for spin transport as it combines low electron effective mass (0.29 m0), a large exchange splitting of the conduction band (1.1 eV), stability in air, and a Curie temperature (about 130 K) among the highest of concentrated ferromagnetic semiconductors. We rationalise the high performance of In2Mn2O7 by the unique combination of a pyrochlore lattice favouring ferromagnetism with an adequate alignment of O–2p, Mn–3d, and In–5s forming a dispersive conduction band while enhancing the Curie temperature.

The successful development of quantum computers is dependent on identifying quantum systems to function as qubits. Paramagnetic states of point defects in semiconductors or insulators have been shown to provide an effective implementation, with the nitrogen-vacancy center in diamond being a prominent example. The spin-1 ground state of this center can be initialized, manipulated, and read out at room temperature. Identifying defects with similar properties in other materials would add flexibility in device design and possibly lead to superior performance or greater functionality. A systematic search for defect-based qubits has been initiated, starting from a list of physical criteria that such centers and their hosts should satisfy. First-principles calculations of atomic and electronic structure are essential in supporting this quest: They provide a deeper understanding of defects that are already being exploited and allow efficient exploration of new materials systems and "defects by design."

Hydrogenation of CO and CO2 to methanol on a stepped copper surface has been calculated using the BEEF-vdW functional and is compared to values derived with RPBE. It is found that the inclusion of vdW forces in the BEEF-vdW functional yields a better description of CO2 hydrogenation as compared to RPBE. These differences are significant for a qualitative description of the overall methanol synthesis kinetics and it is suggested that the selectivity with respect to CO and CO2 is only described correctly with BEEF-vdW.