scholarly journals Oxygen Adsorption Induced Superconductivity in Ultrathin FeTe Film on SrTiO3(001)

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4584
Author(s):  
Wei Ren ◽  
Hao Ru ◽  
Kun Peng ◽  
Huifang Li ◽  
Shuai Lu ◽  
...  
Keyword(s):  
Energy Shift ◽  
Oxygen Adsorption ◽  
Hole Doping ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Iron Chalcogenide ◽  
Microscopic Probe ◽  
Iron Telluride

The phenomenon of oxygen incorporation-induced superconductivity in iron telluride (Fe1+yTe, with antiferromagnetic (AFM) orders) is intriguing and quite different from the case of FeSe. Until now, the microscopic origin of the induced superconductivity and the role of oxygen are far from clear. Here, by combining in situ scanning tunneling microscopy/spectroscopy (STM/STS) and X-ray photoemission spectroscopy (XPS) on oxygenated FeTe, we found physically adsorbed O2 molecules crystallized into c (2/3 × 2) structure as an oxygen overlayer at low temperature, which was vital for superconductivity. The O2 overlayer were not epitaxial on the FeTe lattice, which implied weak O2 –FeTe interaction but strong molecular interactions. The energy shift observed in the STS and XPS measurements indicated a hole doping effect from the O2 overlayer to the FeTe layer, leading to a superconducting gap of 4.5 meV opened across the Fermi level. Our direct microscopic probe clarified the role of oxygen on FeTe and emphasized the importance of charge transfer effect to induce superconductivity in iron-chalcogenide thin films.

Role of the Anion in the Underpotential Deposition of Cadmium on a Rh(111) Electrode:  Probed by Voltammetry and in Situ Scanning Tunneling Microscopy

2005 ◽  
Vol 109 (31) ◽  
pp. 14917-14924 ◽  
Author(s):  
Liang-Yueh Ou Yang ◽  
Fahd Bensliman ◽  
Chia-Haw Shue ◽  
Yaw-Chia Yang ◽  
Ze-Haw Zang ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Underpotential Deposition ◽  
Scanning Tunneling ◽  
Tunneling Microscopy

Ge-Quantum Dots on SI(001) Tailored by Carbon Predeposition

1998 ◽  
Vol 533 ◽  
Author(s):  
O. Leifeld ◽  
D. Grützmacher ◽  
B. Müller ◽  
K. Kern
Keyword(s):  
Surface Roughness ◽  
Critical Thickness ◽  
Carbon Deposition ◽  
Compressive Strain ◽  
Second Step ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Island Nucleation ◽  
Facet Formation

AbstractThe morphology of Si(001) after carbon deposition of 0.05 to 0.11 monolayers (ML) was investigated in situ by ultrahigh vacuum scanning tunneling microscopy (UHV-STM). The carbon induces a c(4×4)-reconstruction of the surface. In addition, carbon increases the surface roughness compared to clean Si(001) (2×1). In a second step, the influence of the carbon induced restructuring on Ge-island nucleation was investigated. The 3D-growth sets in at considerably lower Ge coverage compared to the clean Si(001) (2×1) surface. This leads to a high density of small though irregularly shaped dots, consisting of stepped terraces, already at 2.5 ML Ge. Increasing the Ge-coverage beyond the critical thickness for facet formation, the dots show { 105 }- facets well known from Ge-clusters on bare Si(001) (2×1). However, they are flat on top with a (001)-facet showing the typical buckled Ge rows and missing dimers. This indicates that the compressive strain is not fully relaxed in these hut clusters.

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