| AVS 66th International Symposium & Exhibition | |
| 2D Materials | Tuesday Sessions |
| Session 2D+EM+MI+MN+NS+QS-TuM |
| Session: | Novel Quantum Phenomena |
| Presenter: | Qiang Zou, West Virginia University |
| Authors: | Q. Zou, West Virginia University Z. Ge, West Virginia University C. Yan, West Virginia University H. Zhang, West Virginia University L.L. Li, West Virginia University |
| Correspondent: | Click to Email |
Single crystal FeTe exhibits a distinct long-range bicollinear antiferromagnetic order that can be suppressed by alloying with Se, where superconductivity emerges at a critical Se concentration of 0.3 with a TC of 10 K. In this work, we show that this phase transition can be further modulated by reducing the thickness of FeTe1-xSex, downto the single atomic layer limit. High quality single layer FeTe1-xSex films are grown on SrTiO3(001) substrate by molecular beam epitaxy and characterized by scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy. We find the electronic properties are strongly dependent on the Se content. For x < 0.1, hole-like bands cross the Fermi level and form a hole-pocket at the Γ point with no states observed around the M point, indicating no superconductivity. With increasing Se content, the top of the valence bands moves away from the Fermi level, accompanied by a decrease in effective mass at the Γ point. For x > 0.1, the hole pocket at Γ point moves below the Fermi level, and an electron-pocket emerges at M point where a superconducting gap opens with a TC of ~50 K. These findings and their implications for the emergence and stabilization of superconductivity in Fe-based superconductors at reduced dimensions will be presented at the meeting.