Room-temperature ferromagnetism of 2H-SiC-α-Al₂O₃solid solution nanowires and the physical origin

Abstract

In this work we report the first synthesis of 2H-SiC-α-Al2O3 solid solution (SS) nanowires with 2H-SiC as the host phase. The one dimensional (1D) fake binary-system exhibits interesting room-temperature ferromagnetism and spin-glass-like (SGL) behavior. This novel diluted magnetic semiconductor (DMS) was designed on the basis of SiC which is the most promising fundamental semiconductor used in next-generation electronics as the substitute for Si. A systematic investigation of the magnetic properties reveals the origin of the material's room-temperature ferromagnetism and spin-glass behavior. Spin-polarized density functional theory (DFT) calculations reveal that the net moment originates from a strong coupling between atoms around local Si vacancies produced by the SS defect reaction. Unlike random defects derived magnetic behavior, the SS resulted magnetism is significant to be utilized in functional devices since it belongs to a stable crystal structure that is possible to be prepared rationally in a controlled manner.

Flexible Transparent and Free‐Standing SiC Nanowires Fabric: Stretchable UV Absorber and Fast‐Response UV‐A Detector

“…The light emission spectrum obtained using a cathodoluminescence method is presented as Figure S5 (Supporting Information), which implies a similar electron–photon energy transfer feature. The inset of Figure d presents the hypothetical band structure of Al/O doped 2H‐SiC, where rich near‐conduction‐band levels were introduced by impurities and Si vacancies . We previously investigated the density of states using density functional theory (DFT) methods and found these levels to be between the bottom conduction band and valence‐band maximum .…”

“…The inset of Figure d presents the hypothetical band structure of Al/O doped 2H‐SiC, where rich near‐conduction‐band levels were introduced by impurities and Si vacancies . We previously investigated the density of states using density functional theory (DFT) methods and found these levels to be between the bottom conduction band and valence‐band maximum . Therefore, the modified electron structure expands, enormously, the available spectral range of SiC semiconductors, which provides great opportunities to realize SiC as an active material in photonics applications.…”

“…The nanowire quality stands alongside the self‐assembly of the nanowire fabric as another stubborn difficulty, because the occurrence of complex planar stacking faults (SFs) is a ubiquitous and uncontrollable event . This feature and the indirect nature of their bandgap mean that SiC nanowires are seldom applied for photonic purposes because of the screening effects of phonon processes, despite their many advantages, including being well suited to high‐frequency, high‐power, and high‐temperature devices, and possessing anticorrosion and radio resistance properties . We here demonstrate the self‐assembly of 2H‐SiC FTS‐NWsF using airflow‐oriented growth to form a nanowire network, and the elimination of dense planar SFs by the introduction of Al and O dopants.…”

Compositional and structural engineering of inorganic nanowires toward advanced properties and applications

“…For instance, through control of the vacancy distribution, singlephoton emission could be realized in some materials, 32,33 while a macroscopic property change (ie, enhanced conductivity, varied light emission, modified mechanical behavior, improved sensor performance, and so on) could be obtained in most semiconductor nanowires. [34][35][36][37][38][39] In nanowires with heterojunctions, a specific built-in electric field in the depletion region could be constructed by rationally matching the energy band diagrams, which largely determines the carrier behavior in binary systems, that is, injection into the host nanowire, formation of a 1D electron (hole) gas in the confined region, and so on. When working in the sensor mode, such nanowires display interesting tunable performance.…”

Electronic and magnetism properties of two-dimensional stacked nickel hydroxides and nitrides

“…Besides, the flexible electronic properties 8 9 10 11 12 and fascinating optical properties 13 14 of many novel 2D stacked layered heterostructures have been investigated by theoretical calculation. Recently, spin-based devices 15 16 17 18 19 20 21 22 plays an extremely important role in the relatively novel field of microelectronic and computer sciences. The most exciting event in recent years may be the discovery of the giant magnetoresistance (GMR) effect in metallic multilayer films 23 24 and the successful application of this effect to information storage.…”