Novel Superconducting Semiconducting Superlattices: Dislocation-Induced Superconductivity?

Fogel, N. Ya.; Pokhila, A. S.; Bomze, Yuriy; Sipatov, A. Yu.; Fedorenko, A. I.; Shekhter, R. I.

doi:10.1103/physrevlett.86.512

Cited by 40 publications

(28 citation statements)

References 8 publications

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“…In one early study of dislon theory [76], we have shown that the T c is determined by this competition effect: when the quantum effect is dominant, then T c is increased, and vice versa. The computed T c shows good agreement with a number of existing experimental data; particularly, it may provide a feasible explanation of the mysterious dislocation-induced superconductivity [75,119].…”

Section: Discussionsupporting

confidence: 77%

Theory of electron–phonon–dislon interacting system—toward a quantized theory of dislocations

Tsurimaki

Meng

et al. 2018

New J. Phys.

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We provide a comprehensive theoretical framework to study how crystal dislocations influence the functional properties of materials, based on the idea of a quantized dislocation, namely a 'dislon'. In contrast to previous work on dislons which focused on exotic phenomenology, here we focus on their theoretical structure and computational power. We first provide a pedagogical introduction that explains the necessity and benefits of taking the dislon approach and why the dislon Hamiltonian takes its current form. Then, we study the electron-dislocation and phonon-dislocation scattering problems using the dislon formalism. Both the effective electron and phonon theories are derived, from which the role of dislocations on electronic and phononic transport properties is computed. Compared with traditional dislocation scattering studies, which are intrinsically single-particle, loworder perturbation and classical quenched defect in nature, the dislon theory not only allows easy incorporation of quantum many-body effects such as electron correlation, electron-phonon interaction, and higher-order scattering events, but also allows proper consideration of the dislocation's long-range strain field and dynamic aspects on equal footing for arbitrary types of straight-line dislocations. This means that instead of developing individual models for specific dislocation scattering problems, the dislon theory allows for the calculation of electronic structure and electrical transport, thermal transport, optical and superconducting properties, etc, under one unified theory. Furthermore, the dislon theory has another advantage over empirical models in that it requires no fitting parameters. The dislon theory could serve as a major computational tool to understand the role of dislocations on multiple materials' functional properties at an unprecedented level of clarity, and may have wide applications in dislocated energy materials. List of symbols in alphabetical orderA s Classical electron-dislon scattering amplitude A(k 1 , k 2 , k 3 ) Anharmonic coupling constant b k Phonon annihilation operator + b k Phonon creation operator b, b Phonon fields in coherent state form b Burgers vector c ijkl Stiffness tensor OPEN ACCESS RECEIVED R j 0 Atomic coordinate of j th atom in a perfect crystal S Action S Energy flow operator T Dislocation kinetic energy Recently, some of us started to develop a theory based on the quantization of a dislocation and introduced the 'dislon' as the basic quanta of a quantized dislocation for arbitrary types of dislocation lines, including both edge and screw dislocations. Starting from a one-dimensional quantization approach [25, 36, 77], we treated electron [25] and phonon [36] scattering with an individual dislocation, and single electron-interacting dislocation pair scattering [77]. Later, we generalized the one-dimensional approach to a full three-dimensional quantization [76], but focused on the electron-dislocation superconductivity.In this study, we generalize the dislon theory in 3D to include electron...

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Section: Discussionsupporting

confidence: 77%

Theory of electron–phonon–dislon interacting system—toward a quantized theory of dislocations

Tsurimaki

Meng

et al. 2018

New J. Phys.

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“…Finally, we would like to stress that the analysis of polarization-dependent EXAFS performed here to investigate the local strain at the MnSi/Si(111) interface can be widely employed, e.g., to study superconducting lattices 32,33 or heterostructures incorporating topological insulators. 34,35 This methodology provides invaluable information about the local interfacial structure, and may allow to explore its correlation with their fascinating electronic and magnetic properties.…”

Section: Discussionmentioning

confidence: 99%

“…By exploiting the linear polarization of the synchrotron radiation and by orienting the sample with the surface normal either parallel or perpendicular to the electric vector of the impinging x-rays, it is possible to probe either the out-ofplane or in-plane atomic bonds. This analysis provides direct information about strain in well-oriented thin films such as MnSi on Si(111) and could be used to investigate other systems where the local strain at the interface affects their electronic and magnetic properties as in the case of superconducting lattices 32,33 or heterostructures incorporating topological insulators. 34,35 In the following we will describe our results on differently prepared MnSi thin films as a function of film thickness.…”

Section: Introductionmentioning

confidence: 99%

Strain in epitaxial MnSi films on Si(111) in the thick film limit studied by polarization-dependent extended x-ray absorption fine structure

et al. 2016

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We report a study of the strain state of epitaxial MnSi films on Si(111) substrates in the thick film limit (100-500Å) as a function of film thickness using polarization-dependent extended x-ray absorption fine structure (EXAFS). All films investigated are phase-pure and of high quality with a sharp interface between MnSi and Si. The investigated MnSi films are in a thickness regime where the magnetic transition temperature Tc assumes a thickness-independent enhanced value of ≥43 K as compared with that of bulk MnSi, where Tc ≈ 29 K. A detailed refinement of the EXAFS data reveals that the Mn positions are unchanged, whereas the Si positions vary along the out-of-plane [111]-direction, alternating in orientation from unit cell to unit cell. Thus, for thick MnSi films, the unit cell volume is essentially that of bulk MnSi -except in the vicinity of the interface with the Si substrate (thin film limit). In view of the enhanced magnetic transition temperature we conclude that the mere presence of the interface, and its specific characteristics, strongly affects the magnetic properties of the entire MnSi film, even far from the interface. Our analysis provides invaluable information about the local strain at the MnSi/Si(111) interface. The presented methodology of polarization dependent EXAFS can also be employed to investigate the local structure of other interesting interfaces. arXiv:1611.07736v1 [cond-mat.mtrl-sci]

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“…The period of this superconducting interface nanonetwork is 5.2 nm for PbTe/PbS nanostructures. [3][4][5][6] During a comprehensive experimental investigation it was found that two-layer PbTe/PbS heterostructures can be divided nominally into 3 categories (although there is no sharp boundary between these categories). 6 The first category includes samples with semiconducting layer thicknesses d !…”

Section: Techniques For Fabricating the Samples And For Making The Trmentioning

confidence: 99%

Suppression of superconductivity by strong magnetic fields in PbTe/PbS heterostructures with a superconducting interface

Bengus

Sipatov

Yuzephovich

2013

Low Temperature Physics

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This is a comprehensive study of the effect of strong magnetic fields on superconductivity in PbTe/PbS heterostructures with semiconducting layers of different thicknesses. Metallic conductivity and superconductivity (critical temperature T c 6.5 K) in PbTe/PbS heterostructures are caused by inversion of bands along a continuous network of misfit dislocations that develops at the interfaces between semiconductor layers of sufficient thickness (d > 80 nm). With decreasing d the continuity of the superconducting interface is disrupted, T c decreases, and the metallic conductivity changes to a semiconducting type. Disruption of the continuity of the superconducting interface is found to be a necessary condition for observing a magnetic-field induced superconductor-insulator transition (SIT) and has a significant influence on its features: a fan-like set of resistance curves R(T); intersection of the R(B) curves for fields perpendicular, as well as parallel, to the interface; and, negative magnetoresistance. A scaling analysis based on Fisher's theoretical model is carried out for these samples. No evidence of a SIT was observed in heterostructures with a perfect interface. It appears that the SIT effect is related to percolation phenomena characteristic of granular superconductors. V C 2013 AIP Publishing LLC.

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Novel Superconducting Semiconducting Superlattices: Dislocation-Induced Superconductivity?

Cited by 40 publications

References 8 publications

Theory of electron–phonon–dislon interacting system—toward a quantized theory of dislocations

Theory of electron–phonon–dislon interacting system—toward a quantized theory of dislocations

Strain in epitaxial MnSi films on Si(111) in the thick film limit studied by polarization-dependent extended x-ray absorption fine structure

Suppression of superconductivity by strong magnetic fields in PbTe/PbS heterostructures with a superconducting interface

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