A. J. Arko

FERMI SURFACE MEASUREMENTS IN A-15 COMPOUNDS

Publisher Summary It is believed that electronic and/or phononic structure is responsible for the unusual normal state of high-Tc superconductivity. The de Haas–van Alphen (dHvA) effect provides the most direct and highest precision method of Fermi surface determination presently known. This chapter presents new dHvA data in Nb3Sb and compares that data with the various band calculations, while at the same time reviewing the progress of Fermi surface measurements in A15 compounds in general. In the chapter, three separate pieces of Fermi surface are observed that are consistent with cylindrical surfaces and centered at the M point in the Brillouin zone. Excellent topological correspondence and rough quantitative agreement between theory and experiment for the higher frequencies is also explained. The chapter presents not only a qualitative agreement but also a great deal of quantitative agreement that exists between experiment and band structure calculation. The wave function character at Ep is primarily d-like and coming from Nb sites, a rigid band shift can be useful if one recognizes that results are only qualitative.