| AVS 58th Annual International Symposium and Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Thursday Sessions |
| Session MI-ThM |
| Session: | Emerging Magnetic Characterization and Results |
| Presenter: | Wenzhi Lin, Ohio University Nanoscale and Quantum Phenomena Institute |
| Authors: | W. Lin, Ohio University Nanoscale and Quantum Phenomena Institute H.A.H. Al-Brithen, Ohio University Nanoscale and Quantum Phenomena Institute and KAIN, King Saud Univ., Saudi Arabia K.K. Wang, Ohio University Nanoscale and Quantum Phenomena Institute A.V. Chinchore, Ohio University Nanoscale and Quantum Phenomena Institute M. Shi, Ohio University Nanoscale and Quantum Phenomena Institute Y. Liu, Ohio University Nanoscale and Quantum Phenomena Institute N. Takeuchi, Ohio University Nanoscale and Quantum Phenomena Institute A.R. Smith, Ohio University Nanoscale and Quantum Phenomena Institute |
| Correspondent: | Click to Email |
There is much interest in the field of spintronics in which magnetic phenomena are combined with electronic properties to form a new class of materials with added device functionality. An essential area is that of magnetic nanostructures on the surface of semiconductors. Gallium nitride represents one of the most important next generation semiconductors. The possibility for long spin lifetimes in GaN make it attractive as a spintronic material as well.[1] From this perspective, it is important to explore the epitaxial growth of ferromagnetic layers such as Fe at the surface of GaN. New results for the growth of Fe-induced structures on wurtzite GaN will be presented in this talk.
These investigations are carried out using a custom-designed, home-built molecular beam epitaxy/scanning tunneling microscopy (MBE/STM) facility. Growth of iron on GaN is carried out using an Fe effusion cell and at a substrate temperature which is carefully selected in order to produce the highest quality atomically-smooth Fe-induced structures. It is found that the Fe-induced structures on Ga-polar GaN(0001) strongly depends on the presence of the pseudo-1×1 surface structure as a starting surface, and that under the correct conditions a clear 6×6 reconstructed island structure grows outward from the GaN step edges, as revealed in scanning tunneling microscopy images. First-principles theoretical calculations have been carried out which suggest a low-energy model for the 6×6 structure consisting of Fe atoms embedded within the pseudo-1×1 layer and with Ga adatoms at the top.
The results for N-polar GaN(0001) are quite different. In this case, deposition of Fe onto a Ga-rich surface results in the formation of uniform-height Fe-induced islands having a 4×2 zigzag row structure. The zigzag rows orient along the high symmetry [1120] directions of the surface.
Efforts are also underway to investigate the chemical stoichiometry, and electronic and magnetic properties of these Fe-induced structures and to explore the evolution of these monolayer films as additional Fe and/or Ga is added to the surface.
This work has been supported by the U.S. Department of Energy, Office of Basic Energy Sciences (Grant No. DE-FG02-06ER46317). Additional support from the National Science Foundation (Grant No. 0730257) is also acknowledged.
Y.L. is now at Los Alamos National Laboratory, Los Alamos, NM.
N.T. was a visiting Presidential Scholar from the Universidad Nacional Autónoma de México during 2010-11.
[1] J.H. Bub, J. Rudolph, F. Natali, F. Semond, and D. Hagele, “Anisotropic electron spin relaxation in bulk GaN,” Appl. Phys. Lett. 95, 192107 (2009).