1Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 2National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 3National Laboratory of Solid State Microstructures & Department of Physics, Nanjing University, Nanjing 210093 4Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK 5Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093
Abstract：HgTe (111) surface is comprehensively studied by scanning tunneling microscopy/spectroscopy (STS). In addition to the primitive $(1\times 1)$ hexagonal lattice, six reconstructed surface structures are observed: $(2\times 2)$, $2\times 1$, $4\times 1$, $3\times \sqrt{3}$, $2\sqrt{2}\times 2$ and $\sqrt{11}\times 2$. The $(2\times 2)$ reconstructed lattice maintains the primitive hexagonal symmetry, while the lattices of the other five reconstructions are rectangular. Moreover, the topographic features of the $3\times \sqrt{3}$ reconstruction are bias dependent, indicating that they have both topographic and electronic origins. The STSs obtained at different reconstructed surfaces show a universal dip feature with size $\sim $100 mV, which may be attributed to the surface distortion. Our results reveal the atomic structure and complex reconstructions of the cleaved HgTe (111) surfaces, which paves the way to understand the rich properties of HgTe crystal.
2018, Vol. 35 
