Zobrazeno 1 - 10
of 96
pro vyhledávání: '"Schober, H. R."'
Autor:
Schober, H. R., Peng, H. L.
Publikováno v:
Phys. Rev. E 93, 052607 (2016)
We investigate the origin of the breakdown of the Stokes-Einstein relation (SER) between diffusivity and viscosity in undercooled melts. A binary Lennard-Jones system, as a model for a metallic melt, is studied by molecular dynamics. A weak breakdown
Externí odkaz:
http://arxiv.org/abs/1604.02045
Autor:
Buchenau, U., Schober, H. R.
Publikováno v:
Phil. Mag. 88, 33-35, 3885 (2008)
The boson peak in metallic glasses is modeled in terms of local structural shear rearrangements. Using Eshelby's solution of the corresponding elasticity theory problem (J. D. Eshelby, Proc. Roy. Soc. A241, 376 (1957)), one can calculate the saddle p
Externí odkaz:
http://arxiv.org/abs/0803.2230
Publikováno v:
Physical Review B 76, 064206 (2007)
We show that the same physical mechanism is fundamental for two seemingly different phenomena such as the formation of two-level systems in glasses and the Boson peak in the reduced density of low-frequency vibrational states g(w)/w^2. This mechanism
Externí odkaz:
http://arxiv.org/abs/0706.0730
Autor:
Kluge, M., Schober, H. R.
Publikováno v:
Phys. Rev. B 70, 224209 (2004)
Using molecular dynamics simulation, we calculate the distribution of atomic jum ps in Cu$_{33}$Zr$_{67}$ in the liquid and glassy states. In both states the distribution of jump lengths can be described by a temperature independent exponential of th
Externí odkaz:
http://arxiv.org/abs/cond-mat/0502609
Autor:
Schober, H. R.
Publikováno v:
J. Phys.: Condens. Matter 16, S2659 (2004)
The dynamics of a soft sphere model glass, studied by molecular dynamics, is investigated. The vibrational density of states divided by $\omega^2$ shows a pronounced boson peak. Its shape is in agreement with the universal form derived for soft oscil
Externí odkaz:
http://arxiv.org/abs/cond-mat/0502611
Autor:
Schober, H. R.
Publikováno v:
Phys. Chem. Chem. Phys. 6, 3654 (2004)
We report results of molecular dynamics simulations of a binary Lennard-Jones system at zero pressure in the undercooled liquid and glassy states. We first follow the evolution of diffusivity and dynamic heterogeneity with temperature and show their
Externí odkaz:
http://arxiv.org/abs/cond-mat/0502610
Publikováno v:
Phys. Rev. B 71, 014209 (2005)
The inelastic scattering intensities of glasses and amorphous materials has a maximum at a low frequency, the so called Boson peak. Under applied hydrostatic pressure, $P$, the Boson peak frequency, $\omega_{\rm b}$, is shifted upwards. We have shown
Externí odkaz:
http://arxiv.org/abs/cond-mat/0407565
Publikováno v:
Phys. Rev. B 67, 094203 (2003)
We show that a {\em vibrational instability} of the spectrum of weakly interacting quasi-local harmonic modes creates the maximum in the inelastic scattering intensity in glasses, the Boson peak. The instability, limited by anharmonicity, causes a co
Externí odkaz:
http://arxiv.org/abs/cond-mat/0203165
Autor:
Schober, H. R.
Publikováno v:
J. Non-Crystalline Solids 307, 40 (2002)
The motion of the structure determining components is highly collective, both in amorphous solids and in undercooled liquids. This has been deduced from experimental low temperature data in the tunneling regime as well as from the vanishing isotope e
Externí odkaz:
http://arxiv.org/abs/cond-mat/0112267
Autor:
Schober, H. R.
Publikováno v:
Phys. Rev. Lett. 88, 145901 (2002)
Using molecular dynamics simulation, we have calculated the pressure dependence of the diffusion constant in a binary Lennard-Jones Glass. We observe four temperature regimes. The apparent activation volume drops from high values in the hot liquid to
Externí odkaz:
http://arxiv.org/abs/cond-mat/0111277