Abstract Body

High-quality FeSe_1-xTe_x (0 ≤ x ≤ 1) single crystals were successfully synthesized, with sizes reaching several mm². Crystals with 0 ≤ x ≤ 0.5 were obtained using the chemical vapor transport (CVT) method, while those with 0.5 < x ≤ 1 were obtained through a combination of the self-flux method and annealing [1]. Electromagnetic transport measurements were conducted to establish the complete phase diagram of FeSe_1-xTe_x single crystals. These measurements included the temperature dependence of resistivity, Hall resistivity, and magnetoresistance. The nonlinear Hall resistivity and linear magnetoresistance indicate the presence of Dirac-like small bands with high mobility in crystals with 0 ≤ x ≤ 0.2 and 0.41 ≤ x ≤ 0.6 [2, 3]. Based on the phase diagram, it is suggested that these small bands with high mobility have a positive influence on superconductivity. The origin of Dirac like states may be closely related to the strange metal and related quantum critical point(QCP)[4, 5].

References

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[2]. Y. Sun, T. Taen, T. Yamada, S. Pyon, et al., Multiband Effects and Possible Dirac Fermions in Fe1+yTe0.6Se0.4, Phys. Rev. B 89, 144512 (2014).
[3]. M. D. Watson, T. Yamashita, S. Kasahara, et al., Dichotomy between the hole and electron behavior in multiband superconductor FeSe probed by ultrahigh magnetic fields. Phys. Rev. Lett., 115, 027006, (2015).
[4]. M. Čulo, M. Berben, Y.-T. Hsu, et al., Putative Hall Response of the Strange Metal Component in FeSe1-xSx, Phys. Rev. Res. 3, 023069 (2021).
[5]. S. Licciardello, J. Buhot, J. Lu, et al., Electrical Resistivity across a Nematic Quantum Critical Point, Nature 567, 7747 (2019).

Acknowledgment

This work was partly supported by the National Key R&D Program of China (Grant No. 2018YFA0704300), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB25000000),