Thermal conductivity of materials based on interfacial atomic mixing

Abstract

The Si/Ge single interface and superlattice structure with atom mixing interfaces are constructed. The effects of interfacial atomic mixing on thermal conductivity of single interface and superlattice structures are studied by non-equilibrium molecular dynamics simulation (NEMD). The effects of the number of atomic mixing layers, temperature, total length of the system and period length on the thermal conductivity of different lattice structures are studied. The results show that the mixing of two and four layers of atoms can improve the thermal conductivity of Si/Ge lattice with single interface and the superlattice with small total length due to the "bridge" mechanism. When the total length of the system is large, the thermal conductivity of the superlattice with atomic mixing interfaces decreases significantly compared with the perfect interfaces. The interfacial atom mixing will destroy the phonon coherent transport in the superlattice and decrease the thermal conductivity to some extent. The superlattice with perfect interfaces have obvious temperature effect, while the thermal conductivity of the superlattices with atomic mixing is less sensitive to temperature.

Nanodot embedding based optimization of interfacial thermal conductance

“…形式的 Si/Ge 界面处声子透射率的影响.结果表明，随着粗糙度的增加，两种界面 的声子的透射率均增大，热导率比完美界面时分别提高了 22.3%和 11.1%.本课题 组使用非平衡态分子动力学(NEMD)方法，研究了 Si/Ge 单界面和超晶格结构热 导率受界面原子混合影响的规律 [12] .结果表明，由于声子的"桥接"机制,单一界 面和少周期数的超晶格的热导率受 2 层和 4 层界面原子混合影响而提高；但是在 多周期体系中,由于声子局域化效应，原子混合界面结构与完美界面相比热导率 较低.Han 等 [13] 通过第一性原理计算方法研究了多种合金元素对金刚石/铜界面 性质的影响，研究表明由于合金元素与碳原子键合增强的原因，合金元素能提高 金刚石/铜的界面结合，从而提高了 ITC.…”