scholarly journals Long range and highly tunable interaction between local spins coupled to a superconducting condensate

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Felix Küster ◽  
Sascha Brinker ◽  
Samir Lounis ◽  
Stuart S. P. Parkin ◽  
Paolo Sessi
Keyword(s):  
Interatomic Distance ◽  
Rational Design ◽  
Magnetic Moments ◽  
Scanning Tunneling Spectroscopy ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Design Strategies ◽  
High Tunability ◽  
Atomic Manipulation ◽  
Superconducting Condensate

AbstractInterfacing magnetism with superconducting condensates is rapidly emerging as a viable route for the development of innovative quantum technologies. In this context, the development of rational design strategies to controllably tune the interaction between magnetic moments is crucial. Here we address this problem demonstrating the possibility of tuning the interaction between local spins coupled through a superconducting condensate with atomic scale precision. By using Cr atoms coupled to superconducting Nb, we use atomic manipulation techniques to precisely control the relative distance between local spins along distinct crystallographic directions while simultaneously sensing their coupling by scanning tunneling spectroscopy. Our results reveal the existence of highly anisotropic interactions, lasting up to very long distances, demonstrating the possibility of crossing a quantum phase transition by acting on the direction and interatomic distance between spins. The high tunability provides novel opportunities for the realization of topological superconductivity and the rational design of magneto-superconducting interfaces.

Direct Nanoscale Patterning by Atomic Manipulation

1995 ◽  
Vol 380 ◽  
Author(s):  
Craig T. Salling
Keyword(s):  
Scanning Tunneling Microscope ◽  
Room Temperature ◽  
Atomic Layer ◽  
Sample Surface ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Nanoscale Patterning ◽  
Direct Patterning ◽  
Scale Structures ◽  
Atomic Manipulation

ABSTRACTThe ability to create atomic-scale structures with the scanning tunneling microscope (STM) plays an important role in the development of a future nanoscale technology. I briefly review the various modes of STM-based fabrication and atomic manipulation. I focus on using a UHV-STM to directly pattern the Si(001) surface by atomic manipulation at room temperature. By carefully adjusting the tip morphology and pulse voltage, a single atomic layer can be removed from the sample surface to define features one atom deep. Segments of individual dimer rows can be removed to create structures with atomically straight edges and with lateral features as small as one dimer wide. Trenches ∼3 nm wide and 2–3 atomic layers deep can be created with less stringent control of patterning parameters. Direct patterning provides a straightforward route to the fabrication of nanoscale test structures under UHV conditions of cleanliness.

Scanning Tunneling Spectroscopy

2021 ◽  
pp. 363-378
Author(s):  
C. Julian Chen
Keyword(s):  
Sample Surface ◽  
Experimental Methods ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Atomic Scale ◽  
Detailed Account ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
High Tc ◽  
Spectroscopy Experiment

This chapter discusses various aspects of scanning tunneling spectroscopy (STS). It is an extension of the classical tunneling spectroscopy experiment to nanometer-scale or atomic-scale features on the sample surface. First, the electronics for STS is presented. The nature of STS as a convolution of tip DOS and sample DOS is discussed. Special tip treatment for the STS experiment, often different from the atomic-resolution STM, is described. The purpose is to produce tips with flat DOS, instead of special tip orbitals. Experimental methods to determine tip DOS is discussed. A detailed account of the inelastic scanning tunneling spectroscopy, or STM-IETS, is then discussed. It includes the principles, the electronics, and the instrumental broadening of the features. This chapter concludes with the STS study of superconductors, especially High-Tc supercondoctors.

scholarly journals Atomic-scale interface engineering of Majorana edge modes in a 2D magnet-superconductor hybrid system

2019 ◽  
Vol 5 (7) ◽  
pp. eaav6600 ◽  
Author(s):  
Alexandra Palacio-Morales ◽  
Eric Mascot ◽  
Sagen Cocklin ◽  
Howon Kim ◽  
Stephan Rachel ◽  
...  
Keyword(s):  
Hybrid System ◽  
Theoretical Calculations ◽  
Real Space ◽  
Scanning Tunneling Spectroscopy ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Edge States ◽  
Interface Engineering ◽  
New Paradigm ◽  
Topological Quantum

Topological superconductors are predicted to harbor exotic boundary states—Majorana zero-energy modes—whose non-Abelian braiding statistics present a new paradigm for the realization of topological quantum computing. Using low-temperature scanning tunneling spectroscopy, here, we report on the direct real-space visualization of chiral Majorana edge states in a monolayer topological superconductor, a prototypical magnet-superconductor hybrid system composed of nanoscale Fe islands of monoatomic height on a Re(0001)-O(2 × 1) surface. In particular, we demonstrate that interface engineering by an atomically thin oxide layer is crucial for driving the hybrid system into a topologically nontrivial state as confirmed by theoretical calculations of the topological invariant, the Chern number.

scholarly journals Atomic-scale determination of band offsets at the Gd2O3/GaAs (100) hetero-interface using scanning tunneling spectroscopy

2011 ◽  
Vol 99 (21) ◽  
pp. 212101 ◽  
Author(s):  
Y. P. Chiu ◽  
B. C. Huang ◽  
M. C. Shih ◽  
J. Y. Shen ◽  
P. Chang ◽  
...  
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Band Offsets

MAGNETISM AT THE SPATIAL LIMIT

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3272-3272
Author(s):  
H. MANOHARAN
Keyword(s):  
Distinct Point ◽  
Magnetic Moments ◽  
Atomic Scale ◽  
Spin Coupling ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Magnetic Structures ◽  
Atom Manipulation ◽  
And Control ◽  
Communication Methods

In this talk I will survey our recent experimental results in the detection and manipulation of magnetism at the spatial limit. Our experiments rely on atom manipulation techniques and scanning tunneling microscopy at low temperatures to enable atomic-scale imaging and control. We have observed "quantum mirages" in focusing devices of order 10 nanometers in size, built by assembling structures out of individual atoms. We have directly imaged the spin perturbations due to isolated magnetic moments on a metal surface. The detection of this localized magnetism can then be utilized in a type of teleportation experiment, in which the spectroscopic signature of an atom is sampled and projected to a remote location by means of a surrounding sea of electrons confined in an engineered nanostructure. The quantum mirage thus cast by a single magnetic atom can be coherently refocused at a distinct point where it is detected as a phantom atom around which the electronic structure mimics that at the real atom. Once materialized, this phantom can interact with real matter in intriguing ways. We have constructed other nanoscale magnetic structures which either elucidate the coupling between isolated moments or provide a mechanism for controlling and exploiting spin coupling over long distances. We have also been developing novel communication methods based on the fundamental effects we have discovered.

scholarly journals Topological superconductivity in skyrmion lattices

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Eric Mascot ◽  
Jasmin Bedow ◽  
Martin Graham ◽  
Stephan Rachel ◽  
Dirk K. Morr
Keyword(s):  
Complex Structure ◽  
Magnetic Layer ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Topological Superconductors ◽  
And Topology ◽  
Topological Quantum ◽  
Spin Triplet ◽  
Atomic Manipulation ◽  
Topological Superconductivity

AbstractAtomic manipulation and interface engineering techniques have provided an intriguing approach to custom-designing topological superconductors and the ensuing Majorana zero modes, representing a paradigm for the realization of topological quantum computing and topology-based devices. Magnet-superconductor hybrid (MSH) systems have proven to be experimentally suitable to engineer topological superconductivity through the control of both the complex structure of its magnetic layer and the interface properties of the superconducting surface. Here, we demonstrate that two-dimensional MSH systems containing a magnetic skyrmion lattice provide an unprecedented ability to control the emergence of topological phases. By changing the skyrmion radius, which can be achieved experimentally through an external magnetic field, one can tune between different topological superconducting phases, allowing one to explore their unique properties and the transitions between them. In these MSH systems, Josephson scanning tunneling spectroscopy spatially visualizes one of the most crucial aspects underlying the emergence of topological superconductivity, the spatial structure of the induced spin–triplet correlations.

scholarly journals Atomic-scale intermolecular interaction of hydrogen with a single VOPc molecule on the Au(111) surface

RSC Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 6240-6245
Author(s):  
Jinoh Jung ◽  
Shinjae Nam ◽  
Christoph Wolf ◽  
Andreas J. Heinrich ◽  
Jungseok Chae
Keyword(s):  
Molecular Dynamics ◽  
Atomic Force Microscopy ◽  
Intermolecular Interaction ◽  
Scanning Tunneling Spectroscopy ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Force Microscopy ◽  
Hydrogen Molecules ◽  
Atomic Force ◽  
Micro Cavity

Molecular dynamics of hydrogen molecules trapped in micro-cavity between atomic-scale tip and VOPc molecules on surface and intermolecular interactions have been studied by using scanning tunneling spectroscopy and atomic force microscopy at atomic-scale.

Resolution in the scanning tunneling microscope

1991 ◽  
Vol 49 ◽  
pp. 488-489
Author(s):  
R. J. Wilson ◽  
D. D. Chambliss ◽  
S. Chiang ◽  
V. M. Hallmark
Keyword(s):  
Scanning Tunneling Microscope ◽  
Fundamental Principle ◽  
Atomic Scale ◽  
Lateral Resolution ◽  
Scanning Tunneling ◽  
Electronic Noise ◽  
Vertical Resolution ◽  
Tunneling Microscopy ◽  
Spatial Profile ◽  
Theoretical Analyses

Scanning tunneling microscopy (STM) has been used for many atomic scale observations of metal and semiconductor surfaces. The fundamental principle of the microscope involves the tunneling of evanescent electrons through a 10Å gap between a sharp tip and a reasonably conductive sample at energies in the eV range. Lateral and vertical resolution are used to define the minimum detectable width and height of observed features. Theoretical analyses first discussed lateral resolution in idealized cases, and recent work includes more general considerations. In all cases it is concluded that lateral resolution in STM depends upon the spatial profile of electronic states of both the sample and tip at energies near the Fermi level. Vertical resolution is typically limited by mechanical and electronic noise.

Scanning tunneling microscopy of polymers: A status report

1989 ◽  
Vol 47 ◽  
pp. 330-331
Author(s):  
P.E. Russell ◽  
I.H. Musselman
Keyword(s):  
High Resolution ◽  
Scanning Tunneling Microscopy ◽  
Sample Surface ◽  
Atomic Scale ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Status Report ◽  
Tunneling Microscopy ◽  
Research Issues ◽  
Wide Range

Scanning tunneling microscopy (STM) has evolved rapidly in the past few years. Major developments have occurred in instrumentation, theory, and in a wide range of applications. In this paper, an overview of the application of STM and related techniques to polymers will be given, followed by a discussion of current research issues and prospects for future developments. The application of STM to polymers can be conveniently divided into the following subject areas: atomic scale imaging of uncoated polymer structures; topographic imaging and metrology of man-made polymer structures; and modification of polymer structures. Since many polymers are poor electrical conductors and hence unsuitable for use as a tunneling electrode, the related atomic force microscopy (AFM) technique which is capable of imaging both conductors and insulators has also been applied to polymers.The STM is well known for its high resolution capabilities in the x, y and z axes (Å in x andy and sub-Å in z). In addition to high resolution capabilities, the STM technique provides true three dimensional information in the constant current mode. In this mode, the STM tip is held at a fixed tunneling current (and a fixed bias voltage) and hence a fixed height above the sample surface while scanning across the sample surface.

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