<i>I</i>4/<i>mcm</i>-Si<sub>48</sub>: An Ideal Topological Nodal-Line Semimetal
Laiyuan Su, Shifang Li, Jin Li, Chaoyu He, Xu-Tao Zeng, Xian‐Lei Sheng, Tao Ouyang, Chunxiao Zhang, Chao Tang, Jianxin Zhong
Abstract
Topological semimetals (TSMs) have attracted much attention due to their exotic physical properties and great application potential. Silicon-based TSMs are of particularly importance because of their abundance, nontoxicity, and natural compatibility with the current semiconductor industry. In this work, an ideal low-energy topological nodal-line semimetal (TNLSM) silicon (I4/mcm-Si48) with a clean band crossing at the Fermi level is screened from thousands of silicon allotropes by general and transferable tight-binding and DFT calculations. The results of formation energy, phonon dispersion, ab initio molecular dynamics, and elastic constants show that I4/mcm-Si48 possesses good stability and is more stable than several synthesized silicon structures. Furthermore, I4/mcm-Si48 exhibits exotic photoelectric properties, and the Dirac fermions with high Fermi velocity (3.4–4.36 × 105 m/s) can be excited by low-energy photons. Our study provides a promising topological nodal-line semimetal for fundamental research and potential applications in semiconductor-compatible high-speed photoelectric devices.