Yu-Shiba-Russinov states around an excess iron in FeSe<sub>0.4</sub>Te<sub>0.6</sub>
ORAL
Abstract
Zero-energy bound states have been detected at interstitial excess irons in the iron-based superconductor Fe(Se,Te) by using a scanning tunneling microscope (STM) [1], and its relationship to the Majorana quasiparticles (QP) has been discussed [2]. However, higher energy resolution of the order of ~10 μeV is necessary to make clear the origin of the bound states at the excess irons.
Here, we performed high-energy resolution (~20 μeV) tunneling spectroscopy around excess irons, using a dilution-refrigerator STM [3]. We found that most of the excess irons indicate only finite energy peaks. We also found excess irons with the zero energy peak, but it splits into a pair of finite energy peaks with increasing the distance from the excess irons and with changing the set-point conductance. These findings suggest that the bound states at the excess irons are not Majorana QP in origin but associated with the conventional Yu-Shiba-Russinov state.
[1] J-X. Yin et al., Nat. Phys. 11, 543 (2015).
[2] K. Jiang et al., Phys. Rev. X 9, 011033 (2019)
[3] T. Machida et al., Rev. Sci. Instrum. 89, 0930707 (2018).
Here, we performed high-energy resolution (~20 μeV) tunneling spectroscopy around excess irons, using a dilution-refrigerator STM [3]. We found that most of the excess irons indicate only finite energy peaks. We also found excess irons with the zero energy peak, but it splits into a pair of finite energy peaks with increasing the distance from the excess irons and with changing the set-point conductance. These findings suggest that the bound states at the excess irons are not Majorana QP in origin but associated with the conventional Yu-Shiba-Russinov state.
[1] J-X. Yin et al., Nat. Phys. 11, 543 (2015).
[2] K. Jiang et al., Phys. Rev. X 9, 011033 (2019)
[3] T. Machida et al., Rev. Sci. Instrum. 89, 0930707 (2018).
–
Presenters
-
Tadashi Machida
RIKEN, RIKEN CEMS
Authors
-
Tadashi Machida
RIKEN, RIKEN CEMS
-
Yue Sun
Department of Physics and Mathematics, Aoyama Gakuin University
-
Sunseng Pyon
Department of Applied Physics, The University of Tokyo, University of Tokyo
-
Shun Takeda
Laboratory for Materials and Structures, Tokyo Institute of Technology
-
Yuhki Kohsaka
RIKEN
-
Tetsuo Hanaguri
Center for Emergent Matter Science, RIKEN, RIKEN, CEMS, RIKEN, RIKEN CEMS
-
Takao Sasagawa
Tokyo Inst. of Tech., Laboratory for Materials and Structures, Tokyo Institute of Technology
-
Tsuyoshi Tamegai
Department of Applied Physics, The University of Tokyo, Department of Applied Physics, University of Tokyo