State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People's Republic of China.
Phys Rev Lett. 2010 Sep 10;105(11):117003. doi: 10.1103/PhysRevLett.105.117003. Epub 2010 Sep 8.
The three-dimensional band structure and superconducting gap of Ba0.6K0.4Fe2As2 are studied with angle-resolved photoemission spectroscopy. In contrast with previous results, we have identified three holelike Fermi surface sheets near the zone center with sizable out-of-plane or kz dispersion. The superconducting gap on certain Fermi surface sheets shows significant kz dependence. Moreover, the superconducting gap sizes are different at the same Fermi momentum for two bands with different spatial symmetries (one odd, one even). Our results further reveal the three-dimensional and orbital-dependent structure of the superconducting gap in iron pnictides, which facilitates the understanding of momentum-integrated measurements and provides a distinct test for theories.
采用角分辨光电子能谱研究了 Ba0.6K0.4Fe2As2 的三维能带结构和超导能隙。与先前的结果不同，我们在近区中心确定了三个具有相当大的面外或 kz 色散的空穴型费米面片。在某些费米面片上，超导能隙表现出明显的 kz 依赖性。此外，对于两个具有不同空间对称性（一个奇，一个偶）的能带，在相同费米动量处的超导能隙大小不同。我们的结果进一步揭示了铁磷化物中超导能隙的三维和轨道依赖性结构，这有助于理解动量积分测量，并为理论提供了明显的检验。
