Intrinsically localized vibrations and the mechanical properties of α-uranium

Manley, M. E.; Yethiraj, M.; Sinn, H.; Volz, H. M.; Alatas, A.; Lashley, J. C.; Hults, W. L.; Lander, G. H.; Thoma, D. J.; Smith, James L.

doi:10.1016/j.jallcom.2006.09.137

Cited by 15 publications

(10 citation statements)

References 20 publications

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“…1, as noted in Ref. [16]. This enhanced anisotropy is more convincing evidence of ILM involvement in thermal expansion; especially the development of negative thermal expansion along the ILM polarization axis since this is difficult to explain by conventional anharmonic mechanisms.…”

Section: Thermal Expansionsupporting

confidence: 63%

Impact of intrinsic localized modes of atomic motion on materials properties

Manley

2010

Acta Materialia

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Recent neutron and x-ray scattering measurements show intrinsic localized modes (ILMs) in metallic uranium and ionic sodium iodide. Here, the role ILMs play in the behavior of these materials is examined. With the thermal activation of ILMs, thermal expansion is enhanced, made more anisotropic, and, at a microscopic level, becomes inhomogeneous. Interstitial diffusion, ionic conductivity, the annealing rate of radiation damage, and void growth are all influenced by ILMs. The lattice thermal conductivity is suppressed above the ILM activation temperature while no impact is observed in the electrical conductivity. This complement of transport properties suggests that ILMs could improve thermoelectric performance.Ramifications also include thermal ratcheting, a transition from brittle to ductile fracture, and possibly a phase transformation in uranium.

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Section: Thermal Expansionsupporting

confidence: 63%

Impact of intrinsic localized modes of atomic motion on materials properties

Manley

2010

Acta Materialia

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“…Inelastic X-ray and neutron scattering was used by Manley et al [258,259,257] to probe phonon dispersion in α-uranium single crystals. Variation of temperature showed softening, and the abrupt appearance of a new dynamical mode, without a typically observed phase transition.…”

Section: In the Bulk Of Solidsmentioning

confidence: 99%

Discrete breathers — Advances in theory and applications

Flach¹,

Gorbach²

2008

Physics Reports

940

830

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“…Experimentally DBs have been excited in the physical systems of different nature, including macroscopic periodic systems [6][7][8], nonlinear metamaterials, e.g., granular crystals [9][10][11][12][13][14][15][16] and arrays of microme-chanical cantilevers [17][18][19], electrical [20][21][22] and optical lattices [23], superconducting Josephson junction arrays [24,25], etc. DBs can be found in crystal lattices [26], as confirmed by measuring vibrational spectra for alphauranium [27][28][29], helium [30], NaI [31,32], graphite [33], and PbSe [34]. On the other hand, these experimental results in some cases can be interpreted in different ways and they are still debated [35].…”

Section: Introductionmentioning

confidence: 99%

Effect of discrete breathers on macroscopic properties of the Fermi-Pasta-Ulam chain

Korznikova,

Morkina,

Singh

et al. 2019

Preprint

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For a number of crystals the existence of spatially localized nonlinear vibrational modes, called discrete breathers (DBs), has been demonstrated using molecular dynamics and in a few cases the first-principle simulations. High-resolution imaging of DBs is a challenging task due to their relatively short lifetime ranging typically from 10 to 10 3 atomic oscillation periods (1 to 100 ps). Another way to prove that DBs exist consists in evaluation of their effect on macroscopic properties of crystals. In this paper, we study the effect of DBs on macroscopic properties of the Fermi-Pasta-Ulam chain with symmetric and asymmetric potentials. The specific heat, thermal expansion (stress), and Young's modulus are monitored during the development of modulational instability of the zone boundary mode. The instability results in the formation of chaotic DBs followed by the transition to thermal equilibrium when DBs disappear due to energy radiation in the form of small-amplitude phonons. Time evolution of the macroscopic properties during this transition is monitored. It is found that DBs reduce the specific heat for all the considered chain parameters. They increase the thermal expansion when the potential is asymmetric and, as expected, thermal expansion is not observed in the case of symmetric potential. The Young's modulus in the presence of DBs is smaller than in thermal equilibrium for the symmetric potential and for the potential with a small asymmetry, but it is larger than in thermal equilibrium for the potential with greater asymmetry.

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Intrinsically localized vibrations and the mechanical properties of α-uranium

Cited by 15 publications

References 20 publications

Impact of intrinsic localized modes of atomic motion on materials properties

Impact of intrinsic localized modes of atomic motion on materials properties

Discrete breathers — Advances in theory and applications

Effect of discrete breathers on macroscopic properties of the Fermi-Pasta-Ulam chain

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