论文标题
均匀和交替的基因链中的远程电荷运输
Long-Range Charge Transport in Homogeneous and Alternating-Rigidity Chains
论文作者
论文摘要
我们研究了固有的电子和环境因素在跨分子链的远程电荷转运上的相互作用，最多$ n \ sim 80 $单体。我们用紧密的哈密顿量描述了链的分子电子结构。 Landauer-Büttiker探针方法将电子破坏和非弹性散射形式的热效应纳入。在最多10个单位的短链中，我们观察到相干（隧道，弹道）运动和热辅助传导之间的交叉，热效应增强了超出量子相干极限的电流。我们进一步表明，当单体到传统的电子耦合变大时，出现了非常规的（非单调）传输行为。在长链中，我们确定了不同的行为，热效应抑制了低于相干球极限的电导。为了确定显示出非常规且有效的远程运输的分子链的最小模型，我们模拟了具有高刚性和低刚性区域的交替区域的模块化聚合物。模拟表明，令人惊讶的是，尽管电荷相关性受到结构环境条件的显着影响，反映电荷离域，但电阻显示平均效果，并且对这种图案不敏感。我们结论说，高效的远程电荷运输需要工程内部电子参数和环境条件。
We study the interplay of intrinsic-electronic and environmental factors on long-range charge transport across molecular chains with up to $N\sim 80$ monomers. We describe the molecular electronic structure of the chain with a tight-binding Hamiltonian. Thermal effects in the form of electron decoherence and inelastic scatterings are incorporated with the Landauer-Büttiker probe method. In short chains of up to 10 units we observe the crossover between coherent (tunneling, ballistic) motion and thermally-assisted conduction, with thermal effects enhancing the current beyond the quantum coherent limit. We further show that unconventional (non monotonic with size) transport behavior emerges when monomer-to-monomer electronic coupling is made large. In long chains, we identify a different behavior, with thermal effects suppressing the conductance below the coherent-ballistic limit. With the goal to identify a minimal model for molecular chains displaying unconventional and effective long-range transport, we simulate a modular polymer with alternating regions of high and low rigidity. Simulations show that, surprisingly, while charge correlations are significantly affected by structuring environmental conditions, reflecting charge delocalization, the electrical resistance displays an averaging effect, and it is not sensitive to this patterning. We conclude by arguing that efficient long-range charge transport requires engineering both internal electronic parameters and environmental conditions.
