Self-oxidation-formed boron oxide as a tunnel barrier in SmB6 junctions
Self-oxidation-formed boron oxide as a tunnel barrier in SmB6 junctions
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自氧化形成的氧化硼作为 SmB6 结中的隧道势垒
DOI：
10.1016/j.jallcom.2021.159841
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发表时间：
2021
影响因子：
6.2
通讯作者：
Park, W.K.
中科院分区：
文献类型：
--
作者：
Sittler, J.A.;Park, W.K.
六硼化钐(SmB6)属于一类新的量子物质，被称为拓扑近藤绝缘体。利用平面隧道光谱，观察到了与拓扑表面态相互作用的自旋激子的特征。为了揭示这种相互作用的更多细节，研究了用于清洁SmB6晶体表面的等离子体清洗和离子束刻蚀工艺对特性的影响。此外，还分析了等离子体氧化工艺对形成隧道势垒的影响。将电导谱与基于Blonder-Tinkham-Klip wijk模型的模拟结果进行比较，发现具有最高电阻的结也具有最弱的势垒强度。这种看似自相矛盾的观察结果可以通过考虑一种除了B2O3之外还含有B6O或B3O层的屏障来解释。在较高的离子束能量和较低的等离子体氧化功率下，这种亚氧化物的形成似乎最占优势。
Samarium hexaboride (SmB6) belongs to a novel class of quantum matter known as topological Kondo insulators. By utilizing planar tunneling spectroscopy, signatures of spin excitons that interact with the topological surface states have been observed. To uncover additional details about this interaction, the effect on the characteristic features by plasma cleaning and ion beam etching processes, employed to clean the SmB6crystal surface, are examined. Additionally, the effect of the plasma oxidation process used to form the tunnel barrier is analysed. Comparing the conductance spectra to simulations based on the Blonder-Tinkham-Klapwijk model revealed that the junctions with the highest resistances also had the weakest barrier strengths. Such seemingly contradictory observations may be explained by considering a barrier containing layers of B6O or B3O in addition to B2O3. This suboxide formation appears to be most dominant at higher ion beam energies as well as lower plasma oxidation powers.