Nonequilibrium generalised Langevin equation for the calculation of heat transport properties in model 1D atomic chains coupled to two 3D thermal baths.
Nonequilibrium generalised Langevin equation for the calculation of heat transport properties in model 1D atomic chains coupled to two 3D thermal baths.
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DOI：
10.1063/1.4981816
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发表时间：
2016-12
期刊：
影响因子：
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通讯作者：
H. Ness;L. Stella;C. Lorenz;L. Kantorovich
中科院分区：
文献类型：
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作者：
H. Ness;L. Stella;C. Lorenz;L. Kantorovich
我们使用广义朗之万方程方案来研究低维系统的热传输。在这种方法中，中央经典区域连接到两个保持在两种不同温度的真实温泉浴[H.内斯等人，物理学。修订版 B 93, 174303 (2016)]。我们考虑模型铝系统，即连接到三维浴的一维原子链。研究了热传输特性作为链长 N 和浴间温差 ΔT 的函数。我们计算线性响应区域和非线性区域中的传输特性。对于线性电导与链长度的关系，获得了两个不同的定律。对于大温度 (T≳500 K) 和温差 (ΔT≳500 K)，具有 N>18 个原子的链呈现扩散传输机制，并且整个系统存在温度梯度。对于较低温度 (T≲500 K) 和温差 (ΔT≲400 K)，观察到类似于弹道状态的状态。对于较短的链（N≤15）也可以获得这种类似弹道的状态。我们的详细分析表明，较高温度和温差下的行为主要是由于长链内的非和谐效应。
We use a generalised Langevin equation scheme to study the thermal transport of low dimensional systems. In this approach, the central classical region is connected to two realistic thermal baths kept at two different temperatures [H. Ness et al., Phys. Rev. B 93, 174303 (2016)]. We consider model Al systems, i.e., one-dimensional atomic chains connected to three-dimensional baths. The thermal transport properties are studied as a function of the chain length N and the temperature difference ΔT between the baths. We calculate the transport properties both in the linear response regime and in the non-linear regime. Two different laws are obtained for the linear conductance versus the length of the chains. For large temperatures (T≳500 K) and temperature differences (ΔT≳500 K), the chains, with N>18 atoms, present a diffusive transport regime with the presence of a temperature gradient across the system. For lower temperatures (T≲500 K) and temperature differences (ΔT≲400 K), a regime similar to the ballistic regime is observed. Such a ballistic-like regime is also obtained for shorter chains (N≤15). Our detailed analysis suggests that the behaviour at higher temperatures and temperature differences is mainly due to anharmonic effects within the long chains.