Tunneling and electronic structure of the two-gap superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>MgB</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
Physical review. B, Condensed matter and materials physics