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Efficient thermal transport control is a fundamental issue for electronic device applications such as information, communication, and energy storage technologies in modern electronics in order to achieve desired thermal conditions. Structural defects in materials provide a mechanism to adjust the thermal transport properties of these materials on demand. In this context, the effect of structural defects on lattice thermal conductivities of two-dimensional hexagonal binary group-III nitride (XN, X = B, Al, and Ga) semiconductors is systematically investigated by means of classical molecular dynamics simulations performed with recently developed transferable inter-atomic potentials accurately describing defect energies. Here, two different Green-Kubo based approaches and another approach based on non-equilibrium molecular dynamics are compared in order to get an overall understanding. Our investigation clearly shows that defect concentrations of 3% decrease the thermal conductivity of systems containing these nitrites up to 95%. Results hint that structural defects can be used as effective adjustment parameters in controlling thermal transport properties in device applications associated with these materials. Published under an exclusive license by AIP Publishing.

The structure and thermal boundary conductance of the wurtzite GaN/AlN (0001) interface are investigated using molecular dynamics simulation. Simulation results with three different empirical interatomic potentials have produced similar misfit dislocation networks and dislocation core structures. Specifically, the misfit dislocation network at the GaN/AlN interface is found to consist of pure edge dislocations with a Burgers vector of 1/3(1 (2) over bar 10) and the misfit dislocation core has an eight-atom ring structure. Although different interatomic potentials lead to different dislocation properties and thermal conductance values, all have demonstrated a significant effect of misfit dislocations on the thermal boundary conductance of the GaN/AlN (0001) interface. Published under an exclusive license by AIP Publishing.

We present here a new interatomic potential parameter set to predict the thermal conductivity of zirconium trisulfide monolayers. The generated Tersoff-type force field is parameterized using data collected with first-principles calculations. We use non-equilibrium molecular dynamics simulations to predict the thermal conductivity. The generated parameters result in very good agreement in structural, mechanical, and dynamical parameters. The room temperature lattice thermal conductivity (κ) of the considered crystal is predicted to be κxx = 25.69 W m−1 K−1 and κyy = 42.38 W m−1 K−1, which both agree well with their corresponding first-principles values with a discrepancy of less than 5%. Moreover, the calculated κ variation with temperature (200 and 400 K) are comparable within the framework of the accuracy of both first-principles and molecular dynamics simulations, We acknowledge the financial support received from the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 793726 (TELIOTES—Thermal and electronic transport in inorganic–organic thermoelectric superlattices) and the support of the Supercomputing Center of Galicia (CESGA), where the calculations have been made. We also acknowledge financial support by the Ministerio de Economía, Industria y Competitividad (MINECO) under Grant No. FEDER-MAT2017-90024-P, the Severo Ochoa Centres of Excellence Program under Grant No. SEV-2015-0496, and the Generalitat de Catalunya under Grant No. 2017 SGR 1506. The authors acknowledge the fruitful discussions with Dr. Jesús Carrete Montaña at TU Wien.

In this study, by means of classical molecular dynamics simulations, we investigate the thermal-transport properties of hexagonal single-layer, zinc-blend, and wurtzite phases of $\mathrm{BN}$, $\mathrm{Al}\mathrm{N}$, and $\mathrm{Ga}\mathrm{N}$ crystals, which are very promising for the application and design of high-quality electronic devices. With this in mind, we generate fully transferable Tersoff-type empirical interatomic potential parameter sets by utilizing an optimization procedure based on particle-swarm optimization. The predicted thermal properties as well as the structural, mechanical, and vibrational properties of all materials are in very good agreement with existing experimental and first-principles data. The impact of isotopes on thermal transport is also investigated and between approximately $10$ and 50% reduction in phonon thermal transport with random isotope distribution is observed in $\mathrm{BN}$ and $\mathrm{Ga}\mathrm{N}$ crystals. Our investigation distinctly shows that the generated parameter sets are fully transferable and very useful in exploring the thermal properties of systems containing these nitrides.

WOS: 000423886800011, We study the influence of electric field on the electronic energy band structure, zero-temperature ballistic conductivity and optical properties of double quantum wire. System described by double well anharmonic confinement potential is exposed to a perpendicular magnetic field and Rashba and Dresselhaus spin-orbit interactions. Numerical results show up that the combined effects of internal and external agents cause the formation of crossing, anticrossing, camel-back/anomaly structures and the lateral, downward/upward shifts in the energy dispersion. The anomalies in the energy subbands give rise to the oscillation patterns in the ballistic conductance, and the energy shifts bring about the shift in the peak positions of optical absorption coefficients and refractive index changes. (C) 2017 Elsevier B.V. All rights reserved., Scientific and Technological Research Council of Turkey [TUBITAK BIDEB 2211], The authors Y. Karaaslan and B. Gisi would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BIDEB 2211) for doctoral scholarship.

The effect of the off-diagonal Onsager rate coefficient on the relaxation process of iron-group dihalides has been investigated within the framework of statistical equilibrium theory and the thermodynamics of irreversible processes. For this purpose linearized kinetic equations of the total and staggered magnetization is utilized to study the effect of the off-diagonal kinetic coefficient gamma on the temperature dependence of the relaxation times near the first order, critical and multicritical points of the spin-1/2 metamagnetic Ising model. In accordance with the previous results in the literature, we have observed a non-critical maxima of one the relaxation times below the critical temperature according to the values of off-diagonal coefficient. (C) 2011 Elsevier B.V. All rights reserved.