The structural and electronic properties of FeSe ultra-thin layers on Bi$_{ 2}$Se$_{ 3}$ have been investigated with a combination of scanning tunneling microscopy and spectroscopy and angle-resolved photoemission spectroscopy. The FeSe multi-layers, which are predominantly 3-5 monolayers (ML) thick, exhibit a hole pocket-like electron band at \bar{ \Gamma} and a dumbbell-like feature at \bar{ M}, similar to multi-layers of FeSe on SrTiO$_{ 3}$. Moreover, the topological state of the Bi2Se3 is preserved beneath the FeSe layer, as indicated by a heavily \it{ n}-doped Dirac cone. Low temperature STS does not exhibit a superconducting gap for any investigated thickness down to a temperature of 5 K.

Categories: cond-mat.supr-con cond-mat.mes-hall cond-mat.mtrl-sci

Absence of superconductivity in ultra-thin layers of FeSe synthesized on a topological insulator