posted on 2020-12-16, 17:10authored byDechun Zhou, Heping Li, Saiyu Bu, Benwu Xin, Yixuan Jiang, Nan Si, Jiao Sun, Qingmin Ji, Han Huang, Hui Li, Tianchao Niu
Stanene
is a notable two-dimensional topological insulator with
a large spin–orbit-coupling-induced band gap. However, the
formation of surface alloy intermediates during the epitaxial growth
on noble metal substrates prevents the as-grown stanene from preserving
its intrinsic electronic states. Here, we show that an intentionally
prepared 3×3Au2Sn(111) alloy surface is a
suitable inert substrate for growing stanene without the further formation
of a complicated surface alloy by scanning tunneling microscopy. The
Sn tetramer and clover-shaped Sn pentamer are intermediates for the
black-phosphorene-like Sn film at a substrate temperature of <420
K, which transforms to a blue-phosphorene-like stanene with a lattice
constant of 0.50 nm above 500 K. First-principles calculations reveal
that the epitaxial Sn layer exhibits a lattice registry growth mode
and holds a direct energy gap of ∼0.4 eV. Furthermore, interfacial
charge-transfer-induced significant Rashba splitting in its electronic
structure gives it great potential in spintronic applications.