Unconventional Superconductivity in the Novel Layered Superconductor Fe(Te-Se) Investigated by $^{125}$Te NMR on the Single Crystal

Date
Authors
Michioka, Chishiro
Ohta, Hiroto
Matsui, Mami
Yang, Jinhu
Yoshimura, Kazuyoshi
Fang, Minghu
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
We have performed $^{125}$Te NMR on a single crystal of the novel layered superconductor Fe$_{1.04}$Te$_{0.67}$Se$_{0.33}$ for the first time. The spin parts of the Knight shifts for both $H // a$, $H // c$ are suppressed in the superconducting state, indicating the spin singlet superconductivity. At superconducting state, $1/T_{1}$ shows the power-law behavior ($\sim T^{3}$) without any coherent peaks. Observations of the residual density of state and the $T^{3}$-law indicate the presence of the line node in the superconducting gap. In the normal state, $1/T_{1}T$ which probes the \textbf{q}-summation of spin fluctuations enhances at low temperatures. Our results suggest that the superconductivity in Fe$_{1+\delta}$Te$_{1-x}$Se$_{x}$ is stabilized by the growth of the antiferromagnetic spin fluctuations as well as in FeSe.
Comment: 5 pages, 5figures
Keywords
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Citation
Collections