State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China and Collaborative Innovation Center of Quantum Matter, Beijing 100084, People's Republic of China.
Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
Phys Rev Lett. 2014 Apr 4;112(13):136401. doi: 10.1103/PhysRevLett.112.136401. Epub 2014 Mar 31.
We use scanning tunneling microscopy to investigate the (001) surface of a cleaved SmB6 Kondo insulator. Variable temperature dI/dV spectroscopy up to 60 K reveals a gaplike density of state suppression around the Fermi level, which is due to the hybridization between the itinerant Sm 5d band and localized Sm 4f band. At temperatures below 40 K, a sharp coherence peak emerges within the hybridization gap near the lower gap edge. We propose that the in-gap resonance state is due to a collective excitation in magnetic origin with the presence of spin-orbital coupling and mixed valence fluctuations. These results shed new light on the electronic structure evolution and transport anomaly in SmB6.
我们使用扫描隧道显微镜研究了（001）面的劈开 SmB6 超导绝缘体。在高达 60 K 的变温 dI/dV 谱中，我们发现费米能级附近有一个类似能隙的态密度抑制，这是由于巡游的 Sm 5d 带和局域的 Sm 4f 带之间的杂化。在 40 K 以下的温度下，在近下能隙边缘的杂化能隙内出现了一个尖锐的相干峰。我们提出，能隙中的共振态是由于自旋轨道耦合和混合价涨落存在的磁起源的集体激发。这些结果为 SmB6 的电子结构演化和输运异常提供了新的线索。
