Post-growth Fe deposition on the superconductivity of monolayer FeSe films on SrTi O3-δ

Jiao，Xiaotong1,2; Gong，Guanming1; Zhang，Zhiyu1; Dong，Wenfeng1; Ding，Cui1,3; Pan，Minghu2; Wang，Lili1; Xue，Qi Kun1,3,4

2022-06-01

10.1103/PhysRevMaterials.6.064803

Physical Review Materials   Impact Factor & Quartile

2475-9953

The superconductivity in bulk FeSe depends sensitively on the stoichiometry, ditto for the monolayer FeSe films grown on SrTiO3-δ and other substrates. To tune the stoichiometry, we deposit Fe onto monolayer FeSe films after epitaxial growth. Using in situ low-temperature scanning tunneling microscopy/spectroscopy, we find that the postdeposited Fe atoms incorporate into monolayer films and combine with excess Se to form FeSe, with an upper coverage limit of ∼0.4 unit-cell. Consequently, the superconducting gap concentrates in 10 to 12 meV. The work demonstrates a simple method for stoichiometry tuning and improving the spatial uniformity of monolayer FeSe films. Compared with the gap of ∼15 to 20 meV for the annealed films, the smaller superconducting gap indicates weakened FeSe-TiO2 coupling due to interfacial Se atom substitution.

SCI ; EI

English

Others

WOS:000817850500001

20222912368503

Binary alloys ; Iron ; Scanning tunneling microscopy ; Selenium ; Selenium compounds ; Stoichiometry ; Superconducting films ; Temperature ; Thin films ; Titanium dioxide

Iron:545.1 ; Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals:549.3 ; Thermodynamics:641.1 ; Superconducting Materials:708.3 ; Physical Chemistry:801.4 ; Inorganic Compounds:804.2

2-s2.0-85134081061

Scopus

1.State Key Laboratory of Low-Dimensional Quantum Physics,Department of Physics,Tsinghua University,Beijing,100084,China
2.School of Physics & Information Technology,Shaanxi Normal University,Xian,710119,China
3.Beijing Academy of Quantum Information Sciences,Beijing,100193,China
4.Department of Physics,Southern University of Science and Technology,Shenzhen,518055,China

Jiao，Xiaotong,Gong，Guanming,Zhang，Zhiyu,et al. Post-growth Fe deposition on the superconductivity of monolayer FeSe films on SrTi O3-δ[J]. Physical Review Materials,2022,6(6).

Jiao，Xiaotong.,Gong，Guanming.,Zhang，Zhiyu.,Dong，Wenfeng.,Ding，Cui.,...&Xue，Qi Kun.(2022).Post-growth Fe deposition on the superconductivity of monolayer FeSe films on SrTi O3-δ.Physical Review Materials,6(6).

Jiao，Xiaotong,et al."Post-growth Fe deposition on the superconductivity of monolayer FeSe films on SrTi O3-δ".Physical Review Materials 6.6(2022).