论文标题
自旋交叉分子器件中的负差分电阻
Negative Differential Resistance in Spin-Crossover Molecular Devices
论文作者
论文摘要
我们证明，基于低温扫描隧道显微镜（STM）和光谱法，在自旋杂交（SCO）分子设备中明显的负差分电阻（NDR），其中Fe $^{\ Text {ii}} $ SCO分子沉积在表面上。 STM测量结果表明，NDR在底物材料，温度和SCO层数方面具有鲁棒性。这表明NDR与SCO分子的电子结构本质上相关。实验结果由密度功能理论（DFT）支持，具有非平衡绿色功能（NEGF）计算和通用理论模型。虽然DFT+NEGF计算对特殊的原子stm尖端重现了NDR，但效果归因于态的能量依赖性尖端密度，而不是分子本身。因此，我们提出了一个涉及三个具有非常不同空间定位的分子轨道的库仑封锁模型，如分子电子结构所示。
We demonstrate, based on low-temperature scanning tunneling microscopy (STM) and spectroscopy, a pronounced negative differential resistance (NDR) in spin-crossover (SCO) molecular devices, where a Fe$^{\text{II}}$ SCO molecule is deposited on surfaces. The STM measurements reveal that the NDR is robust with respect to substrate materials, temperature, and the number of SCO layers. This indicates that the NDR is intrinsically related to the electronic structure of the SCO molecule. Experimental results are supported by density functional theory (DFT) with non-equilibrium Green's functions (NEGF) calculations and a generic theoretical model. While the DFT+NEGF calculations reproduce NDR for a special atomically-sharp STM tip, the effect is attributed to the energy-dependent tip density of states rather than the molecule itself. We, therefore, propose a Coulomb blockade model involving three molecular orbitals with very different spatial localization as suggested by the molecular electronic structure.
