Thin-film synthesis of superconductor-on-insulator A15 vanadium silicide

We present a new method for thin-film synthesis of the superconducting A15 phase of vanadium silicide with critical temperature higher than 13 K. Interdiffusion between a metallic vanadium film and the underlying silicon device layer in a silicon-on-insulator substrate, at temperatures between 650 and 750 °C, favors formation of the vanadium-rich A15 phase by limiting the supply of available silicon for the reaction. Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction verify the stoichiometry and structure of the synthesized thin films. We measure superconducting critical currents of more than 106 amperes per square centimeter at low temperature in micron-scale bars fabricated from the material, and an upper critical magnetic field of 20 T, from which we deduce a superconducting coherence length of 4 nm, consistent with previously reported bulk values. The relatively high critical temperature of A15 vanadium silicide is an appealing property for use in silicon-compatible quantum devices and circuits.

The plastic crystalline A15 phase of dimethylaminoalane, [N(CH3)2–AlH2]3

The plastic crystalline A15 phase of dimethylaminoalane, [N(CH3)2–AlH2]3, gives a new perspective on aminoalanes, a group of materials that has been known for more than 50 years.

The role of stoichiometry in superconducting Nb1−βSnβ: electronic and vibrational properties from ab initio calculations

Using first principles calculations the electronic, vibrational and superconducting properties of Nb3Sn compounds with different stoichiometry ratios in the A15 phase have been studied.

An ab initio approach on superconducting properties of Mo3X(X = Si,Ga,Ge) compounds

Self-consistent first principles calculations on type II weakly coupled superconducting [Formula: see text] compounds of A15 phase are performed to understand their fundamental characteristics of the electronic, thermal and superconducting properties. The bulk modulus [Formula: see text], Debye temperature [Formula: see text], density of states (DOS) [Formula: see text], electron–phonon coupling constant [Formula: see text], superconducting transition temperature [Formula: see text], and electronic specific heat coefficient [Formula: see text] have been computed in terms of the electronic structure results, obtained by using the tight-binding linear muffin-tin orbital method. It is observed that all the three materials have their electronic properties dominated by d-orbital at Fermi energy. Thermal and superconducting properties calculated here are found to corroborate well with the experimental results of literature.