论文标题
电流引起的分子连接处的解离，超出了振动加热范式：抗束缚电子状态的作用
Current-induced dissociation in molecular junctions beyond the paradigm of vibrational heating: The role of anti-bonding electronic states
论文作者
论文摘要
单分子连接中电子自由度和核自由度之间的相互作用是一种基本机制，这可能导致电流引起的化学键破裂。因此，这对于分子连接的稳定性和分子电子设备的适用性至关重要。在本出版物中，我们使用数值精确的方案研究了分子连接中电流诱导的键破裂，该方案基于层次量子主方程（HQME）方法，以及与核自由度核程度的离散变量表示结合。我们采用了具有分离核电位的分子连接的通用模型，我们确定了导致解离的不同机制，即抗束缚电子状态的电子群体以及振动模式的电流诱导的加热。我们的结果表明，每当反键入状态的电子种群在能量上都是可能的，后者就起着可忽略的作用。因此，电流诱导的加热作为涉及主动抗键键状态的分子连接处解离的来源的显着性仅限于非谐振转运方案，这将逆转分子电子领域的主要范式。
The interaction between electronic and nuclear degrees of freedom in single-molecule junctions is an essential mechanism, which may result in the current-induced rupture of chemical bonds. As such, it is fundamental for the stability of molecular junctions and for the applicability of molecular electronic devices. In this publication, we study current-induced bond rupture in molecular junctions using a numerically exact scheme, which is based on the hierarchical quantum master equation (HQME) method in combination with a discrete variable representation for the nuclear degrees of freedom. Employing generic models for molecular junctions with dissociative nuclear potentials, we identify distinct mechanisms leading to dissociation, namely the electronic population of anti-bonding electronic states and the current-induced heating of vibrational modes. Our results reveal that the latter plays a negligible role whenever the electronic population of anti-bonding states is energetically possible. Consequently, the significance of current-induced heating as a source for dissociation in molecular junctions involving an active anti-bonding state is restricted to the non-resonant transport regime, which reframes the predominant paradigm in the field of molecular electronics.
