Dislocation Mobility in a Quantum Crystal: The Case of Solid<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts/><mml:none/><mml:mn>4</mml:mn></mml:mmultiscripts></mml:math>

Pessoa, Renato; Vitiello, S. A.; Koning, Maurice de

doi:10.1103/physrevlett.104.085301

Cited by 24 publications

(31 citation statements)

References 25 publications

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“…In addition to previous results for the liquid phase based on very similar interaction models [14], our calculations are in very good agreement with experiment for all elastic constants of the bcc phase. A further element in this discussion is that, although conducted for zero temperature, recent VMC and diffusion Monte Carlo results [22,41] do not seem to show this deviation for C 13 in hcp 4 He. To unveil this puzzle it would be extremely useful to renew the experimental data for the elastic constants of hcp 4 He.…”

Section: Resultsmentioning

confidence: 89%

Elastic constants of hcp4He: Path-integral Monte Carlo results versus experiment

2011

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The elastic constants of hcp 4 He are computed using the path-integral Monte Carlo (PIMC) method. The stiffness coefficients are obtained by imposing different distortions to a periodic cell containing 180 atoms, followed by measurement of the elements of the corresponding stress tensor. For this purpose an appropriate path-integral expression for the stress tensor observable is derived and implemented into the PIMC++ package. In addition to allowing the determination of the elastic stiffness constants, this development also opens the way to an explicit atomistic determination of the Peierls stress for dislocation motion using the PIMC technique. A comparison of the results to available experimental data shows an overall good agreement of the density dependence of the elastic constants, with the single exception of C13. Additional calculations for the bcc phase, on the other hand, show good agreement for all elastic constants.

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Section: Resultsmentioning

confidence: 89%

Elastic constants of hcp4He: Path-integral Monte Carlo results versus experiment

2011

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“…More recently, Peña-Ardila, Vitiello, and de Koning (2011) have proposed an alternative path-integral approach in which a suitable expression for the estimation of the stress-tensor is worked out. (1971) and Greywall (1977) are represented with and ▽, respectively; C 44 measurements from Syshchenko, Day, and Beamish (2009) with ; VMC calculations from Pessoa, Vitiello, and de Koning (2010) with △; DMC ground-state calculations from Cazorla, Lutsyshyn, and Boronat (2012) with •. The dashed lines (green) in the plots represent linear fits to the DMC results.…”

Section: Elasticity and Mechanical Propertiesmentioning

confidence: 99%

“…(77), which is always positive, and assume that ln (r d /r c ) ∼ 1. Using the elastic data reported for perfect solid 4 He by Pessoa, Vitiello and de Koning (2010), that is, µ = 17.1 MPa and ν = 0.15, and adopting an usual Burgers vector of modulus b = a/ √ 3 = 2.1Å, one obtains that E elast disl /L ∼ 1 K/Å . Considering now that dislocations in solid 4 He typically are several µm long (see Fig 14), one finally obtains that, at least, E elast disl ∼ 10 4 K. We note that although this rough estimation of the elastic formation energy of line defects is several orders of magnitude larger than the cost of creating, for instance, a vacancy (see Sec.…”

Section: B Dislocationsmentioning

confidence: 99%

Simulation and understanding of atomic and molecular quantum crystals

2017

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Quantum crystals abound in the whole range of solid-state species. Below a certain threshold temperature the physical behavior of rare gases ( 4 He and Ne), molecular solids (H 2 and CH 4 ), and some ionic (LiH), covalent (graphite), and metallic (Li) crystals can be only explained in terms of quantum nuclear effects (QNE). A detailed comprehension of the nature of quantum solids is critical for achieving progress in a number of fundamental and applied scientific fields like, for instance, planetary sciences, hydrogen storage, nuclear energy, quantum computing, and nanoelectronics. This review describes the current physical understanding of quantum crystals formed by atoms and small molecules, as well as the wide palette of simulation techniques that are used to investigate them. Relevant aspects in these materials such as phase transformations, structural properties, elasticity, crystalline defects and the effects of reduced dimensionality, are discussed thoroughly. An introduction to quantum Monte Carlo techniques, which in the present context are the simulation methods of choice, and other quantum simulation approaches (e. g., path-integral molecular dynamics and quantum thermal baths) is provided. The overarching objective of this article is twofold. First, to clarify in which crystals and physical situations the disregard of QNE may incur in important bias and erroneous interpretations. And second, to promote the study and appreciation of QNE, a topic that traditionally has been treated in the context of condensed matter physics, within the broad and interdisciplinary areas of materials science.

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“…Table 3. Elastic stiffness constants C ij for hcp solid He 4 , as computed using the shadow wave function (SWF) formalism as quoted by Pessoa et al 26 and Ardilla et al 27 [Note that …”

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confidence: 99%

“…Watt and Peselnick 3 performed searches in the appropriate parameter ranges as determined by (26) and (27). They found consistently that the optimum choices of the parameters were very close to the upper limits for the case of G − , and also close to the lower limits for the case of G + .…”

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Bounds and self-consistent estimates for elastic constants of polycrystals of hcp solid He4

Berryman

2012

Phys. Rev. B

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Recent advances in methods for computing both Hashin-Shtrikman bounds and related selfconsistent (or CPA) estimates of elastic constants for polycrystals composed of randomly oriented crystals can be applied successfully to hexagonal close packed solid He 4 . In particular, since the shear modulus C 44 of hexagonal close-packed solid He is known to undergo large temperature variations when 20 mK ≤ T ≤ 200 mK, bounds and estimates computed with this class of effective medium methods, while using C 44 → 0 as a proxy for melting, are found to be both qualitatively and quantitatively very similar to prior results obtained using Monte Carlo methods. HashinShtrikman bounds provide significantly tighter constraints on the polycrystal behavior than do the traditional Voigt and Reuss bounds.

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Dislocation Mobility in a Quantum Crystal: The Case of SolidHe4

Cited by 24 publications

References 25 publications

Elastic constants of hcp4He: Path-integral Monte Carlo results versus experiment

Elastic constants of hcp4He: Path-integral Monte Carlo results versus experiment

Simulation and understanding of atomic and molecular quantum crystals

Bounds and self-consistent estimates for elastic constants of polycrystals of hcp solid He4

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