scholarly journals Signatures of two-dimensional superconductivity emerging within a three-dimensional host superconductor

2021 ◽  
Vol 118 (16) ◽  
pp. e2017810118
Author(s):  
Carolina Parra ◽  
Francis C. Niestemski ◽  
Alex W. Contryman ◽  
Paula Giraldo-Gallo ◽  
Theodore H. Geballe ◽  
...  
Keyword(s):  
Coherence Length ◽  
Energy Gap ◽  
Three Dimensional ◽  
Finite Energy ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Spatially Resolved ◽  
Insulating Phase ◽  
2D Superconductors

Spatial disorder has been shown to drive two-dimensional (2D) superconductors to an insulating phase through a superconductor–insulator transition (SIT). Numerical calculations predict that with increasing disorder, emergent electronic granularity is expected in these materials—a phenomenon where superconducting (SC) domains on the scale of the material’s coherence length are embedded in an insulating matrix and coherently coupled by Josephson tunneling. Here, we present spatially resolved scanning tunneling spectroscopy (STS) measurements of the three-dimensional (3D) superconductor BaPb1−xBixO3 (BPBO), which surprisingly demonstrate three key signatures of emergent electronic granularity, having only been previously conjectured and observed in 2D thin-film systems. These signatures include the observation of emergent SC domains on the scale of the coherence length, finite energy gap over all space, and strong enhancement of spatial anticorrelation between pairing amplitude and gap magnitude as the SIT is approached. These observations are suggestive of 2D SC behavior embedded within a conventional 3D s-wave host, an intriguing but still unexplained interdimensional phenomenon, which has been hinted at by previous experiments in which critical scaling exponents in the vicinity of a putative 3D quantum phase transition are consistent only with dimensionality d = 2.

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.

Energy gap distribution on polycrystalline HgBa2CuO4+δ observed by scanning tunneling spectroscopy

1996 ◽  
Vol 46 (S3) ◽  
pp. 1337-1338
Author(s):  
P. Jess ◽  
U. Hubler ◽  
H. P. Lang ◽  
H. -J. Güntherodt ◽  
K. Lüders ◽  
...  
Keyword(s):  
Energy Gap ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling

scholarly journals Scalable Majorana vortex modes in iron-based superconductors

2020 ◽  
Vol 6 (9) ◽  
pp. eaay0443 ◽  
Author(s):  
Ching-Kai Chiu ◽  
T. Machida ◽  
Yingyi Huang ◽  
T. Hanaguri ◽  
Fu-Chun Zhang
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Zero Energy ◽  
Binding Model ◽  
Zero Bias ◽  
Iron Based Superconductors ◽  
Iron Based ◽  
Important Indication

The iron-based superconductor FeTexSe1−x is one of the material candidates hosting Majorana vortex modes residing in the vortex cores. It has been observed by recent scanning tunneling spectroscopy measurement that the fraction of vortex cores having zero-bias peaks decreases with increasing magnetic field on the surface of FeTexSe1−x. The hybridization of two Majorana vortex modes cannot simply explain this phenomenon. We construct a three-dimensional tight-binding model simulating the physics of over a hundred Majorana vortex modes in FeTexSe1−x. Our simulation shows that the Majorana hybridization and disordered vortex distribution can explain the decreasing fraction of the zero-bias peaks observed in the experiment; the statistics of the energy peaks off zero energy in our Majorana simulation are in agreement with the experiment. These agreements lead to an important indication of scalable Majorana vortex modes in FeTexSe1−x. Thus, FeTexSe1−x can be one promising platform having scalable Majorana qubits for quantum computing.

Local Electronic Structure in Ordered Aggregates of Carbon Nanotubes: Scanning Tunneling Microscopy/scanning Tunneling Spectroscopy Study

1998 ◽  
Vol 13 (9) ◽  
pp. 2389-2395 ◽  
Author(s):  
D. L. Carroll ◽  
P. M. Ajayan ◽  
S. Curran
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Scanning Tunneling Microscopy ◽  
Local Density ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Spatially Resolved ◽  
Local Electronic Structure

The recent application of tunneling probes in electronic structure studies of carbon nanotubes has proven both powerful and challenging. Using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), local electronic properties in ordered aggregates of carbon nanotubes (multiwalled nanotubes and ropes of single walled nanotubes) have been probed. In this report, we present evidence for interlayer (concentric tube) interactions in multiwalled tubes and tube-tube interactions in singlewalled nanotube ropes. The spatially resolved, local electronic structure, as determined by the local density of electronic states, is shown to clearly reflect tube-tube interactions in both of these aggregate forms.

Low Density Two-Dimensional Electron Systems Studied by Scanning Tunneling Spectroscopy

2003 ◽  
Vol 42 (Part 1, No. 7B) ◽  
pp. 4809-4815 ◽  
Author(s):  
Markus Morgenstern ◽  
Jan Klijn ◽  
Christian Meyer ◽  
Mathias Getzlaff ◽  
Robert L. Johnson ◽  
...  
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Low Density ◽  
Two Dimensional ◽  
Electron Systems ◽  
Dimensional Electron ◽  
Two Dimensional Electron Systems

SPATIAL EVOLUTION OF THE BACKGROUND CONDUCTANCE IN THE TUNNELING SPECTRA IN Bi2Sr2-xLaxCuO6+δ

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3190-3193
Author(s):  
T. KATO ◽  
T. MACHIDA ◽  
Y. KAMIJO ◽  
K. HARADA ◽  
R. SAITO ◽  
...  
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Spatial Variation ◽  
Energy Gap ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Spatial Evolution ◽  
Local Energy ◽  
Temperature Scanning

The spatial evolution of the background conductance in the tunneling spectra was investigated with low-temperature scanning tunneling spectroscopy on a slightly overdoped Bi 2 Sr 1.74 La 0.26 CuO 6+δ single crystal at 4.2 K. The asymmetry in the background conductance between positive and negative biases strongly correlates with the local energy gap, which shows the inhomogeneous spatial variation: the tunneling spectra become more asymmetric in the regions where the spectra exhibit larger gap value.

Relaxation of Nanostructures on the Si(111)(7×7) Surface by High Temperature Scanning Tunneling Microscopy

1998 ◽  
Vol 05 (03n04) ◽  
pp. 821-832 ◽  
Author(s):  
Ayahiko Ichimiya ◽  
Yoriko Tanaka ◽  
Kazuhiko Hayashi
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Three Dimensional ◽  
Thermal Relaxation ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Temperature Variable ◽  
Long Lifetime ◽  
Temperature Scanning ◽  
Silicon Islands

Single silicon islands have been produced on the Si(111)(7 × 7) surface by a scanning tunneling microscope (STM) tip. Thermal relaxation of the isolated islands is observed by temperature variable scanning tunneling microscopy with strong tip effects. The sizes of islands depend on time t with a functional form of (t0-t)α. It is found that α≃2/3 for single bilayer islands, and α≃1 for three-dimensional ones. During the decomposition of three-dimensional islands, step bunching of over-layers takes place, while the islands have certain facets, like a pyramid just after the creation. At the final stages of the three-dimensional island decompositions, two-dimensional ones with 5 × 5 structure always appear. We have found that characteristic 5 × 5 islands with a long lifetime are formed during relaxation, but the 7 × 7 islands have mostlt a short lifetime. Rotation of small islands is also observed during relaxation. We discuss the results in terms of two-dimensional vapor phase processes.

ON THE ROLE OF KINKS AND STRAIN IN HETEROEPITAXIAL GROWTH: AN STM STUDY

2000 ◽  
Vol 07 (05n06) ◽  
pp. 673-677
Author(s):  
E. LUNDGREN ◽  
M. SCHMID ◽  
G. LEONARDELLI ◽  
A. HAMMERSCHMID ◽  
B. STANKA ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Scanning Tunneling Microscopy ◽  
Three Dimensional ◽  
Growth Mode ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Heteroepitaxial Growth ◽  
Tunneling Microscopy ◽  
Exchange Diffusion

Interlayer diffusion of Co over steps of vacancy islands on the Pt(111) surface as studied by scanning tunneling microscopy is presented. It is demonstrated that Co atoms descend Pt steps by an exchange diffusion process at the step edge with the Pt atoms. Further, the exchange diffusion process is observed to occur at the corners (kinks) of the vacancy islands. The importance of kinks concerning whether the growth mode of a heteropitaxial film is two-dimensional or three-dimensional is demonstrated for the case of thin Co films on Pt(111). We argue that the strain in the Co film is to a large extent responsible for the kink formation.

scholarly journals Zero-energy bound states in the high-temperature superconductors at the two-dimensional limit

2020 ◽  
Vol 6 (13) ◽  
pp. eaax7547 ◽  
Author(s):  
Chaofei Liu ◽  
Cheng Chen ◽  
Xiaoqiang Liu ◽  
Ziqiao Wang ◽  
Yi Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Bound States ◽  
High Temperature Superconductors ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Zero Energy ◽  
Topological Superconductors ◽  
Topological Quantum ◽  
Energy Bound

Majorana zero modes (MZMs) that obey the non-Abelian statistics have been intensively investigated for potential applications in topological quantum computing. The prevailing signals in tunneling experiments “fingerprinting” the existence of MZMs are the zero-energy bound states (ZEBSs). However, nearly all of the previously reported ZEBSs showing signatures of the MZMs are observed in difficult-to-fabricate heterostructures at very low temperatures and additionally require applied magnetic field. Here, by using in situ scanning tunneling spectroscopy, we detect the ZEBSs upon the interstitial Fe adatoms deposited on two different high-temperature superconducting one-unit-cell iron chalcogenides on SrTiO3(001). The spectroscopic results resemble the phenomenological characteristics of the MZMs inside the vortex cores of topological superconductors. Our experimental findings may extend the MZM explorations in connate topological superconductors toward an applicable temperature regime and down to the two-dimensional (2D) limit.

scholarly journals Yu-Shiba-Rusinov bands in ferromagnetic superconducting diamond

2020 ◽  
Vol 6 (20) ◽  
pp. eaaz2536
Author(s):  
Gufei Zhang ◽  
Tomas Samuely ◽  
Naoya Iwahara ◽  
Jozef Kačmarčík ◽  
Changan Wang ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Three Dimensional ◽  
Superconducting Devices ◽  
Electronic States ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Boron Doped Diamond ◽  
Spin Lattice ◽  
Boron Doped ◽  
Potential Applications

The combination of different exotic properties in materials paves the way for the emergence of their new potential applications. An example is the recently found coexistence of the mutually antagonistic ferromagnetism and superconductivity in hydrogenated boron-doped diamond, which promises to be an attractive system with which to explore unconventional physics. Here, we show the emergence of Yu-Shiba-Rusinov (YSR) bands with a spatial extent of tens of nanometers in ferromagnetic superconducting diamond using scanning tunneling spectroscopy. We demonstrate theoretically how a two-dimensional (2D) spin lattice at the surface of a three-dimensional (3D) superconductor gives rise to the YSR bands and how their density-of-states profile correlates with the spin lattice structure. The established strategy to realize new forms of the coexistence of ferromagnetism and superconductivity opens a way to engineer the unusual electronic states and also to design better-performing superconducting devices.

Sign in / Sign up

Export Citation Format

Share Document