کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1817490 | 1525694 | 2015 | 5 صفحه PDF | دانلود رایگان |
• The nanoscale large gap VPG and small gap Δ maps of Fe(Se,Te) were observed by STS.
• The STM topography shows clear atomic structure of ∼0.38 nm spacing.
• The average of large gaps is |VPG| ∼ 305 mV with σ ∼ 48 mV.
• The smallest gap magnitude Δ ∼ 7 meV was estimated by fitting curve.
The nanoscale spatial distributions of large gap-like structure on superconducting FeSe1−xTex were investigated by scanning tunneling microscopy/spectroscopy (STM/STS). The STM topography shows regular atomic lattice arrangements with the lattice spacing ∼0.38 nm, together with the randomly distributed large spots due to the excess Fe atoms. From the STS measurements, the small gap structures of Δ ∼ 7 meV were partly observed. On the other hand, the high-bias dI/dV curves exhibit the broad peak structures at the negative biases of VPG = −200 to −400 mV in the measured whole surface area. The average of these large gaps is |VPGave| ∼ 305 mV with the standard deviation of σ ∼ 48 mV. The spatial distributions of the VPG exhibit the domain structures consisting of the relatively smaller gaps (<250 meV), which correspond to the excess Fe positions. The small gap Δ ∼ 7 meV is also observed at those positions, suggesting that the excess Fe affects the electronic structures of FeSe1−xTex.
Journal: Physica C: Superconductivity and its Applications - Volume 518, 15 November 2015, Pages 23–27