On the interplay of paramagnetism and topology in the Fe-based High Tc Superconductors

Abstract

The high Tc superconductor FeTe0.55Se0.45 has recently been shown to support a surface state with topological character. Here we use low-energy laser-based ARPES with variable light polarization, including both linear and circular polarization, to re-examine the same material and the related FeTe0.7Se0.3, with larger Te concentration. In both cases we observe the presence of a surface state displaying linear dispersion in a cone-like configuration. The use of circular polarization confirms the presence of helical spin structure. These experimental studies are compared with theoretical studies that account for the local magnetic effects related to the paramagnetism observed in this system in the normal state. In contrast to previous studies we find that including the magnetic contributions is necessary to bring the chemical potential of the calculated electronic band structure naturally into alignment with the experimental observations.

References in corpus (3)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Topological Insulators with Inversion Symmetry
• Absence of a Proximity Effect in a Topological Insulator on a Cuprate Superconductor: Bi2Se3/Bi2Sr2CaCu2O8

Cited by in corpus (5)

• Coexistence of Surface Ferromagnetism and Gapless Topological State in MnBi${}_2$Te${}_4$
• Observation of Superconductivity Induced Ferromagnetism in an Fe-Chalcogenide Superconductor
• Emergent vortex Majorana zero mode in iron-based superconductors
• Phase diagrams of superconducting topological surface states
• Fe${}_{1+y}$Te${}_x$Se${}_{1-x}$: a delicate and tunable Majorana material