Abstract
The discovery of superconductivity in MgB2 at Tc = 39 K has initiated great efforts to identify its microscopic origin. A superconducting two-gap structure has been firmly established experimentally. However, the importance of the smaller gap which is essential in pushing Tc above the BCS value of a one-gap superconductor has mostly been ignored. Our results based on ab initio calculations and a newly introduced k, j-dependent bonding indicator show that Mg contributes significantly to states from which the small gap originates. In addition, it is revealed that Mg—B covalent bonding is an important factor in limiting the substitution of Mg in MgB2.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
