THE EFFECT OF OXYGEN ON SUPERCONDUCTIVITY AND MAGNETISM IN Eu1.5Ce0.5RuSr2Cu2O10 +δ

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3650-3654 ◽  
Author(s):  
I. FELNER ◽  
U. ASAF ◽  
Y. LEVI ◽  
O. MILLO
Keyword(s):  
Magnetic Ordering ◽  
Weak Ferromagnetism ◽  
Scanning Tunneling Spectroscopy ◽  
Hole Doping ◽  
Scanning Tunneling ◽  
Normal State Resistivity ◽  
Oxygen Treatment ◽  
Time Scanning ◽  
Effect Of Oxygen ◽  
The Eu

The Eu 1.5 Ce 0.5 RuSr 2 Cu 2 O 10+δ compound is the first known Cu-O based material in which superconductivity (SC) and weak-ferromagnetism (W-FM) coexist (T c =32 K, T M =122 K). SC is confined to the CuO 2 planes, and the magnetic ordering is due to the Ru sublattice. For as-prepared samples (APS), the normal-state resistivity is characteristic of an under-doped SC compound. The hole doping in CuO 2 planes, can be achieved with appropriate variation of the oxygen concentrations, which is obtained by annealing the APS under oxygen pressures up to 150 atm. The effect of oxygen treatment is to shift the onset of SC monotonically, up to 49 K. For 75 atm., two transition temperatures are found, indicating the existence of two SC phases. At the same time, scanning tunneling spectroscopy measurements show spatial variations of the gap with a double-peak distribution.

Scanning-tunneling spectroscopy on conjugated polymer films

2003 ◽  
Vol 771 ◽  
Author(s):  
M. Kemerink ◽  
S.F. Alvarado ◽  
P.M. Koenraad ◽  
R.A.J. Janssen ◽  
H.W.M. Salemink ◽  
...  
Keyword(s):  
Polymer Films ◽  
Conjugated Polymer ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Direct Consequence ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Band Alignment ◽  
Scanning Tunneling ◽  
Order Of Magnitude

AbstractScanning-tunneling spectroscopy experiments have been performed on conjugated polymer films and have been compared to a three-dimensional numerical model for charge injection and transport. It is found that field enhancement near the tip apex leads to significant changes in the injected current, which can amount to more than an order of magnitude, and can even change the polarity of the dominant charge carrier. As a direct consequence, the single-particle band gap and band alignment of the organic material can be directly obtained from tip height-voltage (z-V) curves, provided that the tip has a sufficiently sharp apex.

scholarly journals Spectroscopy of a tunable moiré system with a correlated and topological flat band

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaomeng Liu ◽  
Cheng-Li Chiu ◽  
Jong Yeon Lee ◽  
Gelareh Farahi ◽  
Kenji Watanabe ◽  
...  
Keyword(s):  
Band Structure ◽  
Twist Angle ◽  
Bilayer Graphene ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Flat Band ◽  
Correlated Electron ◽  
Partial Filling ◽  
Valley Polarization ◽  
Spectroscopic Signatures

AbstractMoiré superlattices created by the twisted stacking of two-dimensional crystals can host electronic bands with flat energy dispersion in which enhanced interactions promote correlated electron states. The twisted double bilayer graphene (TDBG), where two Bernal bilayer graphene are stacked with a twist angle, is such a moiré system with tunable flat bands. Here, we use gate-tuned scanning tunneling spectroscopy to directly demonstrate the tunability of the band structure of TDBG with an electric field and to show spectroscopic signatures of electronic correlations and topology for its flat band. Our spectroscopic experiments are in agreement with a continuum model of TDBG band structure and reveal signatures of a correlated insulator gap at partial filling of its isolated flat band. The topological properties of this flat band are probed with the application of a magnetic field, which leads to valley polarization and the splitting of Chern bands with a large effective g-factor.

scholarly journals Imaging and identification of point defects in PtTe2

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Kuanysh Zhussupbekov ◽  
Lida Ansari ◽  
John B. McManus ◽  
Ainur Zhussupbekova ◽  
Igor V. Shvets ◽  
...  
Keyword(s):  
Point Defects ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Density Functional Theory Calculations ◽  
Charge Carrier Mobility ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Recombination Rates ◽  
And Performance

AbstractThe properties and performance of two-dimensional (2D) materials can be greatly affected by point defects. PtTe2, a 2D material that belongs to the group 10 transition metal dichalcogenides, is a type-II Dirac semimetal, which has gained a lot of attention recently due to its potential for applications in catalysis, photonics, and spintronics. Here, we provide an experimental and theoretical investigation of point defects on and near the surface of PtTe2. Using scanning tunneling microscopy and scanning tunneling spectroscopy (STS) measurements, in combination with first-principle calculations, we identify and characterize five common surface and subsurface point defects. The influence of these defects on the electronic structure of PtTe2 is explored in detail through grid STS measurements and complementary density functional theory calculations. We believe these findings will be of significance to future efforts to engineer point defects in PtTe2, which is an interesting and enticing approach to tune the charge-carrier mobility and electron–hole recombination rates, as well as the site reactivity for catalysis.

Scanning Tunneling Spectroscopy

2009 ◽  
Vol 2 (1) ◽  
pp. 37-55 ◽  
Author(s):  
Harold J.W. Zandvliet ◽  
Arie van Houselt
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling

Scanning tunneling spectroscopy of lead sulfide quantum wells fabricated by atomic layer deposition

2010 ◽  
Vol 21 (48) ◽  
pp. 485402 ◽  
Author(s):  
Wonyoung Lee ◽  
Neil P Dasgupta ◽  
Hee Joon Jung ◽  
Jung-Rok Lee ◽  
Robert Sinclair ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Quantum Wells ◽  
Lead Sulfide ◽  
Atomic Layer ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Layer Deposition
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