The electronic structure of Stanene on Cu (111) with angle-resolved photoemission spectroscopy

Shu-Hua Kuo^1*, Jing-Yue Huang², Shih-Wei Chiu¹, Pei-Yu Chuang¹, Horng-Tay Jeng^2,3,4, Ping-Jui Hsu², Cheng-Maw Cheng^1,5,6

¹Condensed Matter Physics Group, 1National Synchrotron Radiation Research Center, Hsinchu, Taiwan
²Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
³Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
⁴Institute of Physics, Academia Sinica, Taipei, Taiwan
⁵Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
⁶Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei, Taiwan

* Presenter:Shu-Hua Kuo, email:kuo.sh@nsrrc.org.tw

Two-dimensional topological insulators (2D-TIs), have been attracting intense attentions during the past ten year in research areas of condensed matter physics owing to their electronic structures associated to a nontrivial band topology and topologically protected edge states. Tin (Sn), a common group IV element, has attracted much attention nowadays, not only for its large spin-orbit coupling (SOC), but also for integration compatible with semiconductor industry. Stanene, one of 2-D group-IV materials, has strong SOC and a large quantum spin Hall (QSH) and quantum anomalous Hall (QAH) gaps (~0.3 eV), which is benefit for room temperature nanoelectronic and optoelectronic applications. Here in, we had successfully growth 𝛼- and β-stanene on Cu (111) substrate by the molecular beam epitaxy (MBE) method. In 𝛼-stanene/Cu (111), a significant QSH and QAH band gap ~ 0.3 eV extracted from the band mapping result shows the consistency of previous study. Moreover, well-ordered β-stanene could be prepared on Cu(111) substrate and confirmed by the low energy electron diffraction (LEED). A novel Dirac state near the zone boundary was observed in the band mapping result, suggesting that β-stanene could be Dirac semimetal or nodal-line Dirac semimetal. In this work, a detail discussion of the band structure of 𝛼- and β-stanene will be presented. The deeper understanding of electronic structure of stanene would be significant in realizing the origin of higher temperature QSH effect.

Keywords: 2D material, MBE, ARPES, band structure, stanene