Molecular and lattice dynamical study on modulated structures in quartz

Semagin, Denis A.; Shigenari, Takeshi; Abe, Kohji; Nagamine, M.; Aslanyan, T. A.

doi:10.1103/physrevb.68.052101

Cited by 11 publications

(7 citation statements)

References 22 publications

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“…This is consistent with the general trend that the incommensurate phase can be more easily realized in crystals with more or less complex structure [18], especially for crystals consisting of comparatively rigid atomic groups with rotational degrees of freedom [23][24][25], although there can be exceptions [26]. Theoretically, incommensurate modulation can appear in a simple lattice [27], but, to the best of our knowledge, no incommensurate phase has been discovered in a pure metal.…”

Section: Indentation Simulationssupporting

confidence: 70%

Theoretical strength of 2D hexagonal crystals: application to bubble raft indentation

Yoshikawa

Shibutani

2005

Philosophical Magazine

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By means of lattice and molecular dynamics we study the theoretical strength of homogeneously strained, defect-free 2D crystals whose atoms interact via pair potentials with short-and longer-ranged interactions, respectively. We calculate the instability surface, i.e. the boundary in the 3D homogeneous strain space (" xx , " yy , " xy ), at which the first vanishing of the frequency of a vibrational mode occurs, taking into account all 2(N À 1) þ 3 modes of a 2D periodic system of N atoms. We also compute the strain energies of the crystal on the instability surface, thus defining the most dangerous direction(s) of strain where the critical energy density is small. A theory is developed to incorporate the effect of loading device-sample interactions in the lattice instability criterion. The results are applied to the model problem of bubble raft indentation. We analyse the distribution of the unstable phonon modes in the first Brillouin zone as a function of the loading parameter, and discuss the post-critical behaviour of the lattice in the presence of strain gradients as in nanoindentation experiments.

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Section: Indentation Simulationssupporting

confidence: 70%

Theoretical strength of 2D hexagonal crystals: application to bubble raft indentation

Yoshikawa

Shibutani

2005

Philosophical Magazine

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“…Despite the simplicity, their force-field parameters are reasonably successful in describing the structural and dynamical properties of SiO 2 systems (see, for example, Refs. [13,[16][17][18][19]). …”

Section: Introductionmentioning

confidence: 97%

Molecular dynamics study of the high‐temperature elasticity of SiO₂ polymorphs: Structural phase transition and elastic anomaly

Kimizuka

Kaburaki²

2005

Physica Status Solidi (b)

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The elastic properties of cristobalite and quartz, the typical polymorphs of SiO 2 , are studied with particular emphasis on the structural phase transition and the high-temperature phase. Using the equilibrium molecular dynamics (MD) method with a stress-fluctuation formula, we have successfully evaluated the adiabatic elastic constants ( ij C ) of both cristobalite and quartz in a wide temperature range, including the a -b phase-transition region. In the results for cristobalite, the anomalous property of a negative Poisson's ratio appears over the entire temperature range of 300 -1800 K, where the bulk modulus is extremely low compared with the shear modulus. However, the mechanisms differ between the a -and bphases, according to the structural data obtained from the MD simulations. On the other hand, quartz exhibits a negative Poisson's ratio in the narrow temperature region between ca. 750 and 825 K before the phase transition occurs. After the transition to the b -phase, the bulk modulus is shown to increase sharply, and a positive value of Poisson's ratio is recovered. For cristobalite as well as quartz, we have confirmed that the recovery of bulk ij C 's in the b -phase can be attributed to internal relaxations, which arise from the cooperative motions of corner-linked SiO 4 tetrahedra.

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“…Reciprocal rotation of tetrahedrons plays an important role in the α-β-phase transition via the incommensurate phase and formation of acoustic properties in quartz in the vicinity of this transition [17][18][19][20]. In the course of analyzing the results obtained on quartz [25][26][27][28][29][30][31][32][33][34] an assumption was made concerning the existence of a relationship between the major effects and the rotational degrees of freedom [35,36].…”

Section: Introductionmentioning

confidence: 99%

Long-period states of a crystal finite-size-particle system

Потекаев

Samsonov

2009

Russ Phys J

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A one-dimensional model is proposed, which ensures description of origination and main properties of longperiod and incommensurate phases of crystal having complex structure and consists of comparatively rigid "atomic clusters". In the case where reciprocal rotations of theses clusters are considerably large, not only translational but also rotational degrees of freedom have to be taken into account for the clusters. It is consideration of the rotational degrees of freedom which might provide for formation of long-period states and development of a number of physical effects, such as a variety of soliton solutions (of domain walls) and their non-trivial dynamics.

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Molecular and lattice dynamical study on modulated structures in quartz

Cited by 11 publications

References 22 publications

Theoretical strength of 2D hexagonal crystals: application to bubble raft indentation

Theoretical strength of 2D hexagonal crystals: application to bubble raft indentation

Molecular dynamics study of the high‐temperature elasticity of SiO₂ polymorphs: Structural phase transition and elastic anomaly

Long-period states of a crystal finite-size-particle system

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Molecular and lattice dynamical study on modulated structures in quartz

Cited by 11 publications

References 22 publications

Theoretical strength of 2D hexagonal crystals: application to bubble raft indentation

Theoretical strength of 2D hexagonal crystals: application to bubble raft indentation

Molecular dynamics study of the high‐temperature elasticity of SiO2 polymorphs: Structural phase transition and elastic anomaly

Long-period states of a crystal finite-size-particle system

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Molecular dynamics study of the high‐temperature elasticity of SiO₂ polymorphs: Structural phase transition and elastic anomaly