Spin Polarization and Magnetic Moment in Silicon Carbide Grown by the Method of Coordinated Substitution of Atoms.

Sergey A Kukushkin,Andrey V Osipov

doi:10.3390/ma14195579

Abstract

In the present work, a new method for obtaining silicon carbide of the cubic polytype 3C-SiC with silicon vacancies in a stable state is proposed theoretically and implemented experimentally. The idea of the method is that the silicon vacancies are first created by high-temperature annealing in a silicon substrate Si(111) doped with boron B, and only then is this silicon converted into 3C-SiC(111), due to a chemical reaction with carbon monoxide CO. A part of the silicon vacancies that have bypassed “chemical selection” during this transformation get into the SiC. As the process of SiC synthesis proceeds at temperatures of ~1350 °C, thermal fluctuations in the SiC force the carbon atom C adjacent to the vacancy to jump to its place. In this case, an almost flat cluster of four C atoms and an additional void right under it are formed. This stable state of the vacancy, by analogy with NV centers in diamond, is designated as a C4V center. The C4V centers in the grown 3C-SiC were detected experimentally by Raman spectroscopy and spectroscopic ellipsometry. Calculations performed by methods of density-functional theory have revealed that the C4V centers have a magnetic moment equal to the Bohr magneton μB and lead to spin polarization in the SiC if the concentration of C4V centers is sufficiently high.

Highlights

Much attention has been paid to the creation of solid-state devices, the operations of which are based not on the charge but the spin of charged particles; the development of new materials with the property of spin polarization is a very important task [1,2,3]
Similar nitrogen-vacancy center (NV) centers in SiC [5,6], as well as some other point defects based on silicon vacancies (VSi) in SiC [4,7], have been intensely studied
Before the synthesis of the SiC epitaxial layer, 3-inch Si(111) substrates doped with B were purified from oxides in a mixture of NH4OH and NH4F, which ensured the passivation of the Si(111) surface with hydrogen atoms [14]

Summary

Introduction

Much attention has been paid to the creation of solid-state devices, the operations of which are based not on the charge but the spin of charged particles; the development of new materials with the property of spin polarization is a very important task [1,2,3]. It was shown that this layer, in contrast to ideal SiC, has a magnetic moment and the property of spin polarization.

Results

Conclusion