Novel bipolar magnetic semiconducting and fully compensated ferrimagnetic semiconducting characters in newly designed LiMgPdSn-type compounds: KCaCX (X = O, S, and Se)

• Published in: Journal of alloys and compounds 2017-07, Vol.710, p.1-7
• Main Authors: Du, Jiangtao, Feng, L.F., Wang, X.T., Qin, Z., Cheng, Z.X., Wang, L.Y.
• Format: Article
• Language: English
• Subjects: 10th century; Alloys; Antiferromagnetism; Bipolar magnetic semiconductor; Distortion; Electron spin; Electronic structure; External pressure; Ferrimagnetism; First-principles calculations; Hydrostatic strain and tetragonal distortion; Magnetic fields; Magnetic moments; Magnetic properties; Magnetic structure; Semi-metal; Semiconductors; Spin-gapless semiconductor; Spintronics; Studies; Temperature
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.03.262

With the first-principles calculations, the electronic structure and magnetic properties of KCaCX (X = O, S and Se) alloys with LiMgPdSn-type structure have been studied. The results show that KCaCO is a new bipolar ferrimagnetic semiconductor (BFS) with an integer magnetic moment of 3.00 μB at the equilibrium lattice parameter, while KCaCS and KCaCSe are fully compensated ferrimagnetic (antiferromagnetic) semiconductors (FCFS). The strong spin polarization mainly derives from the 2p electrons of C element in the KCaCX (X = O, S and Se) compounds. Under the effect of hydrostatic strain and tetragonal distortion, KCaCO alloy undergoes an interesting physics change from bipolar ferrimagnetic semiconductor (BFS) → ferrimagnetic spin-gapless semiconductor (FSGS) → general ferrimagnetic metal (GFM) transition, which indicates that the electronic and magnetic structure could be highly tuned by external temperature or pressure. A physics transition can also be found in KCaCS and KCaCSe compounds: undergoing FCFS → fully compensated ferrimagnetic semi-metal (FCFSM) → general fully compensated ferrimagnetic metal (FCFM) transitions under the hydrostatic strain and tetragonal distortion. Therefore, KCaCX (X = O, S and Se) compounds would be a series of potential candidates for new spintronics device. •KCaCO compound was found to be a novel bipolar magnetic (BMS) semiconductor.•The BMS → spin gapless semiconductor transition (SGS) was found in KCaCO compound.•KCaCX (X = S, Se) were found to be fully compensated ferrimagnetic semiconductors (FCFS).•The FCFS → FCF semi-metal transitions were found in KCaCX (X = S, Se).