Electron energy can oscillate near a crystal dislocation

Li, Mingda; Cui, Wenping; Dresselhaus, M. S.; Chen, Gang

doi:10.1088/1367-2630/aa5710

Cited by 18 publications

(38 citation statements)

References 37 publications

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“…As for a dislocation, inspired by mode-expansion work in 1D 12,13 , we expand the lattice displacement vector caused by a single dislocation line ( ) u R extending along the z-direction with core position 0 0 ( , ) (0,0)…”

Section: The Foundation Of a Quantized Dislocationmentioning

confidence: 99%

Tailoring Superconductivity with Quantum Dislocations

Li¹,

Song²,

Liu³

et al. 2017

Nano Lett.

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Despite the established knowledge that crystal dislocations can affect a material's superconducting properties, the exact mechanism of the electron-dislocation interaction in a dislocated superconductor has long been missing. Being a type of defect, dislocations are expected to decrease a material's superconducting transition temperature (T) by breaking the coherence. Yet experimentally, even in isotropic type I superconductors, dislocations can either decrease, increase, or have little influence on T. These experimental findings have yet to be understood. Although the anisotropic pairing in dirty superconductors has explained impurity-induced T reduction, no quantitative agreement has been reached in the case a dislocation given its complexity. In this study, by generalizing the one-dimensional quantized dislocation field to three dimensions, we reveal that there are indeed two distinct types of electron-dislocation interactions. Besides the usual electron-dislocation potential scattering, there is another interaction driving an effective attraction between electrons that is caused by dislons, which are quantized modes of a dislocation. The role of dislocations to superconductivity is thus clarified as the competition between the classical and quantum effects, showing excellent agreement with existing experimental data. In particular, the existence of both classical and quantum effects provides a plausible explanation for the illusive origin of dislocation-induced superconductivity in semiconducting PbS/PbTe superlattice nanostructures. A quantitative criterion has been derived, in which a dislocated superconductor with low elastic moduli and small electron effective mass and in a confined environment is inclined to enhance T. This provides a new pathway for engineering a material's superconducting properties by using dislocations as an additional degree of freedom.

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Section: The Foundation Of a Quantized Dislocationmentioning

confidence: 99%

Tailoring Superconductivity with Quantum Dislocations

Li¹,

Song²,

Liu³

et al. 2017

Nano Lett.

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“…(3) Consistency of the electron-dislocation relaxation rate with, for instance, the semi-classical result [10]. The proofs can be found in [25,76].…”

Section: Discussionmentioning

confidence: 89%

“…Since the first theoretical predictions of dislocations in 1934 [2][3][4] and experimental observations in 1956 [5][6][7], most dislocation studies have focused on their impacts on materials' mechanical properties, where a pure classical description of dislocations has been proven highly successful [1,8,9]. In addition to their influence on mechanical properties, dislocations are also known to affect a number of materials' functional properties such as electronic structure and electrical transport [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], thermal transport [26][27][28][29][30][31][32][33][34][35][36], optical properties [37][38][39][40][41][42][43][44][45][46][47]…”

Section: Introductionmentioning

confidence: 99%

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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“…Dynamic scattering DPI models describe a mechanism also referred to as "fluttering", which was a later advancement in the static DPI theory and according to which, a dislocation absorbs an incident phonon, vibrates and subsequently re-emits a phonon [62,64,65]. Recent advances towards a unified description of DPI are based on phonon renormalization, with a model that treats the DPI in the framework of quantum field theory and dislocations as quantized fields, named "dislons" [63,66]. Ab initio methods have been proven successful for the prediction of thermal transport [23,67,68,69,70], although very few of them address the effect of dislocations [23,68], due to the large volume of the supercells required for the modeling of these defects.…”

Section: Introductionmentioning

confidence: 99%

Decorated Dislocations against Phonon Propagation for Thermal Management

Giaremis

Kioseoglou

Desmarchelier

et al. 2020

ACS Appl. Energy Mater.

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Τhe impact of decorated dislocations on the effective thermal conductivity of GaN is investigated by means of equilibrium molecular dynamics simulations via the Green-Kubo approach. The formation of "nanowires" by a few atoms of In in the core of dislocations in wurtzite GaN is found to affect the thermal properties of the material, as it leads to a significant decrease of the thermal conductivity, along with an enhancement of its anisotropic character. The thermal conductivity of In-decorated dislocations is compared to the ones of pristine GaN, InN, and a random and an ordered InxGa1-xN alloy, to examine the impact of doping. Results are explained by the stress maps, the bonding properties and the phonon density of states of the aforementioned systems. The decorated dislocations engineering is a novel way to tune, among other transport properties, the effective thermal conductivity of materials at the nanoscale, which can lead to the manufacturing of interesting candidates for thermoelectric or anisotropic thermal dissipation devices.

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Electron energy can oscillate near a crystal dislocation

Cited by 18 publications

References 37 publications

Tailoring Superconductivity with Quantum Dislocations

Tailoring Superconductivity with Quantum Dislocations

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

Decorated Dislocations against Phonon Propagation for Thermal Management

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