Tunable Magnetic States on the Zigzag Edges of Hydrogenated and Halogenated group-IV Nanoribbons
Tzu-Cheng Wang1,2*, Chia-Hsiu Hsu1, Zhi-Quan Huang1, Feng-Chuan Chuang1, Wan-Sheng Su3,4, Guang-Yu Guo2,5
1Department of physics, National Sun Yat-Sen University, Kaohsiung, Taiwan
2Department of physics and Center for theoretical Sciences, National Taiwan university, Taipei, Taiwan
3Experimentation Division, National Taiwan Science Education Center, Taipei, Taiwan
4Department of Electro-Optical Engineering, National Taipei University of Technology, Taipei, Taiwan
5Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
* presenting author:TzuCheng Wang, email:r04222073@ntu.edu.tw
The magnetic and electronic properties of hydrogenated and halogenated group-IV zigzag nanoribbons (ZNRs) are investigated by first-principles density functional calculations. Fascinatingly, we find that all the ZNRs have magnetic edges with a rich variety of electronic and magnetic properties tunable by selecting the parent and passivating elements as well as controlling the magnetization direction and external strain. In particular, the electric property of the edge band structure can be tuned from the conducting to insulating with a band gap up to 0.7 eV. The last controllability would allow us to develop magnetic on-off nano-switches. Furthermore, ZNRs such as SiI, Ge, GeI and SnH, have fully spin-polarized metallic edge states and thus are promising materials for spintronics. The calculated magnetocrystalline anisotropy energy can be as large as ~9 meV/edge-site, being 2×103 time greater than that of bulk Ni and Fe (~5 μeV/atom), and thus has great potential for high density magneto-electric data-storage devices. Finally, the calculated exchange coupling strength and thus magnetic transition temperature increases as the applied strain goes from −5% to 5%. Our findings thus show that these ZNRs would have exciting applications in next-generation electronic and spintronic nano-devices.

Keywords: first-principles calculation, nanoribbon, electronic structure, magnetic edge state