Author/Authors :
Nakashima، نويسنده , , Y. and Ino، نويسنده , , A. and Nagato، نويسنده , , S. and Anzai، نويسنده , , H. and Iwasawa، نويسنده , , H. and Utsumi، نويسنده , , Y. and Sato، نويسنده , , H. and Arita، نويسنده , , M. and Namatame، نويسنده , , H. and Taniguchi، نويسنده , , M. and Oguchi، نويسنده , , T. and Aiura، نويسنده , , Y. and Hase، نويسنده , , I. and Kihou، نويسنده , , K. and Lee، نويسنده , , C.H. and Iyo، نويسنده , , A. and Eisaki، نويسنده , , H.، نويسنده ,
Abstract :
We report an angle-resolved photoemission study of BaFe2As2, a parent compound of iron-based superconductors. Low-energy tunable excitation photons have allowed the first observation of three-dimensional saddle-point dispersion at the Z point, as well as the Γ point. This resolves a discrepancy in Fermi-surface studies. We found that these van Hove singularities are not only involved in three-dimensional Fermi-surface reconstruction with antiferromagnetic ordering but also renormalized and predominant at low energies. Hence, the Fermi-surface instability due to these singularities would also underlie the associated superconductors.
Keywords :
A. Iron pnictides , D. Phase transition , C. Electronic band structure , E. Angle-resolved photoemission spectroscopy
