Quantum anomalous Hall effect with tunable Chern number in magnetic topological insulator film
Quantum anomalous Hall effect with tunable Chern number in magnetic topological insulator film
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DOI：
10.1103/physrevb.85.045445
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发表时间：
2011-10
影响因子：
3.7
通讯作者：
Hua Jiang;Z. Qiao;Haiwen Liu;Q. Niu
中科院分区：
文献类型：
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作者：
Hua Jiang;Z. Qiao;Haiwen Liu;Q. Niu
为了研究分子与光子场之间的相互作用，包括等离子体光子场和外部光子场，我们在有和没有扫描隧道显微镜(STM)针尖的Au衬底上对卟啉分子的光致发光(PL)进行了原位测量。测量是在超高真空扫描隧道显微镜中进行的，在He-Cd激光照射期间，入射功率在10(-3)到10(-7)W范围内变化。在大约10(-7)W的入射功率下，光谱强烈依赖于STM针尖的存在，而STM针尖与分子的STM发光有关。在激光功率为7.5×10~(-8)W、激光束径为40微米、有效面积为2 nm的条件下，根据实验观测到的分子扫描隧道显微镜诱导光发射(STML/PL)的量子效率比，估算了STML的量子效率比。据估计，STML中一个电子的量子效率大约是PL中一个光子的量子效率的10倍。这种反常增强将在STM纳米腔中分子的等离子体增强光发射的基础上进行讨论。(C)2012年美国物理研究所。[DOI：10.1063/1.3680597]
In order to study the interaction between molecules and photon fields, including plasmonic and external laser fields, we have carried out in situ measurements of photoluminescence (PL) from porphyrin molecules on Au substrates with and without a scanning tunneling microscope (STM) tip. Measurements were performed in a ultra-high vacuum scanning tunneling microscope chamber during irradiation by a He-Cd laser with incident power varying in the 10(-3) to 10(-7) W range. At an incident power of around 10(-7) W, the spectra depend strongly on the presence of STM tip, which is associated with STM light emission from molecules. We estimated the ratio of quantum efficiency of scanning tunneling microscope-induced light emission (STML) from molecules to PL on the basis of the STML/PL intensity ratio observed experimentally at a laser power of 7.5 x 10(-8) W, with the use of a 40 mu m laser beam diameter and an effective area of 2 nm for STML. The estimated quantum efficiency for an electron in STML is roughly 10(10) times larger than that for one photon of PL. This anomalous enhancement will be discussed on the basis of plasmon-enhanced light emission from molecules in a STM nano-cavity. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3680597]