Special Issue "Quantum Crystals"

A special issue of Crystals (ISSN 2073-4352).

Deadline for manuscript submissions: closed (31 March 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Claudio Cazorla

University of New South Wales (UNSW) Australia, School of Materials Science and Engineering, Sydney, Australia
Website | E-Mail
Interests: materials science; quantum solids; first-principles simulation methods; phase transitions; multiferroics
Co-Guest Editor
Prof. Dr. Jordi Boronat

Polytechnic University of Catalonia, Department of Physics and Nuclear Engineering, Barcelona, Spain
Website | E-Mail
Interests: condensed matter physics, quantum liquids, Bose-Einstein condensation; quantum crystals; quantum Monte Carlo

Special Issue Information

Dear Colleagues,

At low temperatures, the kinetic energy per particle in a quantum crystal is much larger than kBT (where kB represents the Boltzmann constant and T the temperature) and the spatial fluctuations of the atoms around their equilibrium lattice positions are up to ~10% of the distance to the neighboring lattice sites. These intriguing qualities can be understood only in terms of quantum mechanical arguments.

The study of quantum crystals is very important to understand nature. Hydrogen and helium, two archetypal quantum species, are the most abundant elements in the universe and thus an exhaustive knowledge of their condensed matter phases is crucial for understanding the chemical composition and past and future evolution of planetary bodies. Quantum solids are also sought after for technological applications, including high-pressure synthesis, nuclear energy, gas storage, quantum computing, and nanoelectronics.

We invite investigators to submit research papers discussing the experimental and theoretical understanding of quantum crystals. Quantum crystals include, but are not limited to, rare-gases (e.g., He and Ne), light-weight molecular crystals (e.g., H2 and CH4), light-weight covalent, ionic and metallic solids (e.g., graphite, LiH, and Li), quantum paraelectrics (e.g., SrTiO3 and KTaO3), Wigner crystals, vortex lattices, and dipole systems.

The potential topics for this Special Issue include, but are not restricted to:

-    Experimental synthesis and characterization of quantum crystals
-    Theory and simulation 
-    Crystalline defects in quantum crystals
-    Elastic and mechanical properties
-    Quantum low-dimensional systems (i.e., thin films, one-dimensional systems, and clusters)
-    Quantum solids at high-pressure conditions
-    Gas-storage and structural properties of quantum materials
-    H-bonded ferroelectrics and quantum paraelectrics

Prof. Dr. Claudio Cazorla
Prof. Dr. Jordi Boronat
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Helium
  • Hydrogen
  • Zero-point motion
  • Isotopic effects
  • Quantum simulation methods
  • Crystalline defects
  • Quantum materials

Published Papers (2 papers)

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Research

Open AccessArticle Exciton Spectroscopy of Spatially Separated Electrons and Holes in the Dielectric Quantum Dots
Crystals 2018, 8(4), 148; doi:10.3390/cryst8040148
Received: 26 February 2018 / Revised: 23 March 2018 / Accepted: 25 March 2018 / Published: 27 March 2018
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Abstract
It is shown that in the potential energy of an exciton of spatially separated electrons and holes (hole moves in the amount of quantum dots (QDs), and the electron is localized on a spherical surface section (QD—dielectric matrix)) taking into account centrifugal energy
[...] Read more.
It is shown that in the potential energy of an exciton of spatially separated electrons and holes (hole moves in the amount of quantum dots (QDs), and the electron is localized on a spherical surface section (QD—dielectric matrix)) taking into account centrifugal energy gives rise band of the quasi-stationary surface exciton states that with the increase of the radius of QD becomes stationary state. The mechanisms of formation of the spectra of interband and intraband absorption (emission) of light in nanosystems containing aluminum oxide QDs, placed in the matrix of vacuum oil, are presented. It is shown that the electron transitions in the area of the surface exciton states cause significant absorption in the visible and near infrared wavelengths, and cause the experimentally observed significant blurring of the absorption edge. Full article
(This article belongs to the Special Issue Quantum Crystals)
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Open AccessArticle Dislocation Structure and Mobility in Hcp Rare-Gas Solids: Quantum versus Classical
Crystals 2018, 8(2), 64; doi:10.3390/cryst8020064
Received: 13 December 2017 / Revised: 17 January 2018 / Accepted: 20 January 2018 / Published: 29 January 2018
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Abstract
We study the structural and mobility properties of edge dislocations in rare-gas crystals with the hexagonal close-packed (hcp) structure by using classical simulation techniques. Our results are discussed in the light of recent experimental and theoretical studies on hcp 4He, an archetypal
[...] Read more.
We study the structural and mobility properties of edge dislocations in rare-gas crystals with the hexagonal close-packed (hcp) structure by using classical simulation techniques. Our results are discussed in the light of recent experimental and theoretical studies on hcp 4 He, an archetypal quantum crystal. According to our simulations classical hcp rare-gas crystals present a strong tendency towards dislocation dissociation into Shockley partials in the basal plane, similarly to what is observed in solid helium. This is due to the presence of a low-energy metastable stacking fault, of the order of 0.1 mJ/m 2 , that can get further reduced by quantum nuclear effects. We compute the minimum shear stress that induces glide of dislocations within the hcp basal plane at zero temperature, namely, the Peierls stress, and find a characteristic value of the order of 1 MPa. This threshold value is similar to the Peierls stress reported for metallic hcp solids (Zr and Cd) but orders of magnitude larger than the one estimated for solid helium. We find, however, that in contrast to classical hcp metals but in analogy to solid helium, glide of edge dislocations can be thermally activated at very low temperatures, T∼10 K, in the absence of any applied shear stress. Full article
(This article belongs to the Special Issue Quantum Crystals)
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