First-principles study on the origin of ferromagnetism in n-type Cu-doped ZnO

• Published in: Solid state communications 2012-06, Vol.152 (12), p.1057-1060
• Main Authors: Fang, D.Q., De Sarkar, Abir, Zhang, R.Q.
• Format: Article
• Language: English
• Subjects: A. Semiconductors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Magnetic property; E. First-principles; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Magnetic properties and materials; Magnetic semiconductors; Physics; Semiconductor compounds; Studies of specific magnetic materials
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2012.03.025

Based on the density functional calculations with the GGA+U correction, we elucidate the origin of the experimentally reported ferromagnetism in n-type Cu-doped ZnO. Pure Cu-doped ZnO shows the unoccupied 3d states in the gap introduced by Cu, resulting in the insulating ground state and weak magnetic exchange interactions, in contrast to the half-metallic ground state and high ferromagnetic stability predicted by the calculations without U correction. However, the electron traps induced by Cu in n-type Cu-doped ZnO may lead to the partial occupancy of the Cu gap states, which stabilize the ferromagnetic ordering between two Cu atoms. ► Revealed the origin of the experimental ferromagnetism arising in n-type Cu-doped ZnO. ► Found that ZnO doped by Cu shows the unoccupied 3d states in the gap introduced by Cu. ► Recognized electron traps induced by Cu atoms, which stabilizes the ferromagnetic ordering.