Atomically smooth ultrathin films of topological insulator Sb2Te3
Topological insulator, electronic structure, scanning tunneling microscopy, angle-resolved photoemission spectroscopy, molecular beam epitaxy
The growth and characterization of single-crystalline thin films of topological insulators (TIs) is an important step towards their possible applications. Using in situ scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES), we show that moderately thick Sb2Te3 films grown layer-by-layer by molecular beam epitaxy (MBE) on Si(111) are atomically smooth, single-crystalline, and intrinsically insulating. Furthermore, these films were found to exhibit a robust TI electronic structure with their Fermi energy lying within the energy gap of the bulk that intersects only the Dirac cone of the surface states. Depositing Cs in situ moves the Fermi energy of the Sb2Te3 films without changing the electronic band structure, as predicted by theory. We found that the TI behavior is preserved in Sb2Te3 films down to five quintuple layers (QLs).
Tsinghua University Press
Guang Wang,Xiegang Zhu,Jing Wen,Xi Chen,Ke He,Lili Wang,Xucun Ma,Ying Liu,Xi Dai,Zhong Fang,Jinfeng Jia,Qikun Xue, Atomically smooth ultrathin films of topological insulator Sb2Te3. NanoRes.2010, 3(12): 874–880