Graphene-like Be3X2 (X = C, Si, Ge, Sn): A new family of two-dimensional topological insulators<xref rid="cpb_28_3_037101_fn1" ref-type="fn">*</xref><fn id="cpb_28_3_037101_fn1"><label>*</label>Project supported by the National Natural Science Foundation of China (Grant Nos. 11674136 and 11564022), the Thousand Talents Plan — the Recruitment Program for Young Professionals, China (Grant No. 1097816002), Yunnan Province for Recruiting High-Caliber Technological Talents, China (Grant No. 1097816002), Reserve Talents for Yunnan Young and Middle-aged Academic and Technical Leaders, China (Grant No. 2017HB010), the Academic Qinglan Project of Kunming University of Science and Technology (KUST), China (Grant No. 1407840010), the Analysis and Testing Fund of KUST, China (Grant No. 2017M20162230010), and the High-level Talents of KUST, China (Grant No. 1411909425).</fn>

Graphene-like Be₃X₂ (X = C, Si, Ge, Sn): A new family of two-dimensional topological insulators**

Project supported by the National Natural Science Foundation of China (Grant Nos. 11674136 and 11564022), the Thousand Talents Plan — the Recruitment Program for Young Professionals, China (Grant No. 1097816002), Yunnan Province for Recruiting High-Caliber Technological Talents, China (Grant No. 1097816002), Reserve Talents for Yunnan Young and Middle-aged Academic and Technical Leaders, China (Grant No. 2017HB010), the Academic Qinglan Project of Kunming University of Science and Technology (KUST), China (Grant No. 1407840010), the Analysis and Testing Fund of KUST, China (Grant No. 2017M20162230010), and the High-level Talents of KUST, China (Grant No. 1411909425).

Song Lingling¹, Zhang Lizhi², Guan Yurou¹, Lu Jianchen¹, Yan Cuixia^{1, †}, Cai Jinming^{1, ‡}

(a) Optimized configuration of Be₃Si₂ monolayer with a unit cell labeled by black dashed line. The green and blue spheres represent Be and Si, respectively. (b) Phonon-dispersion curves, where the left inset indicates the first Brillouin zone, and the right inset shows the electron localization function of the Be₃Si₂ monolayer with the iso-value of 0.96.