Our previous analytical studies [10] and molecular dynamics simulations [11] have revealed the dramatic decrease of phonon thermal conductivity in quasi-one-dimensional nanostructures

with rough (porous) surface and edge layers. Methods In the semiquantum molecular dynamics approach, the dynamics of the system is described with the use of the classical Newtonian equations of motion while the effects of phonon quantum statistics are introduced through random Langevin-like forces with a specific power spectral density (the color noise). If the random forces are delta-correlated Nutlin-3a in a time domain, this corresponds to the white noise with a flat power spectral PCI-32765 ic50 density. This situation corresponds to high-enough temperatures, when k B T is larger than the quantum of the highest phonon frequency mode in the system, . However, for low-enough temperature, , the stochastic dynamics of the system should

be described with the use of random Langevin-like forces with a non-flat power spectral density, which corresponds to the system with color noise. For the generation of color noise with the power spectrum, consistent with the quantum Selleckchem Elacridar fluctuation-dissipation theorem, we use the method which was developed in [2]. The semiquantum molecular dynamics approach has allowed us to model the transition in the rough-edge nanoribbons from the thermal insulator-like behavior at high temperature, when the thermal conductivity decreases with the conductor length Thiamine-diphosphate kinase (see [11]), to the ballistic conductor-like behavior at low temperature, when the thermal conductivity increases with the conductor length. Here, we apply the semiquantum molecular dynamics approach for the modeling of temperature dependence of thermal phonon conductivity in silicon and germanium nanoribbons with rough edges. We show that the presence of rough edges significantly decreases the room-temperature thermal conductivity of the nanoribbon and results in the weakly pronounced maximum of

thermal conductivity at low temperatures. The latter property is closely related with the absence of (or weak) anharmonicity of the lattice potential and correspondingly weak anharmonic (Umklapp) scattering. In our semiquantum molecular dynamics approach, we make use neither of the quantum corrections to classically predicted thermal conductivity, e.g., discussed in [12], nor of the values of Umklapp or surface roughness-induced scattering rates, calculated independently from molecular dynamics simulation, e.g., discussed in [13, 14]. To diminish the contact (interface) boundary resistance between the nanoribbon and heat reservoirs, e.g., discussed in [15], we model the nanoribbon with relatively long parts, immersed in semiquantum heat baths (see also [2]).