2006 APS March Meeting
Monday–Friday, March 13–17, 2006;
Baltimore, MD
Session K12: Focus Session: Magnetic Thin Films and Narrow Gap Semiconductors
2:30 PM–5:18 PM,
Tuesday, March 14, 2006
Baltimore Convention Center
Room: 304
Sponsoring
Units:
DMP DCMP
Chair: Juliet Correa, University of Muenster
Abstract ID: BAPS.2006.MAR.K12.1
Abstract: K12.00001 : Subsurfactant Epitaxy for Ferromagnetic Semiconductors
2:30 PM–3:06 PM
Preview Abstract
Abstract
Author:
Hanno H. Weitering
(The University of Tennessee and Oak Ridge National Laboratory)
In this talk, I will discuss a discovery that is expected to have due
impacts in two forefront areas of materials research. First, I will
introduce ``subsurfactant epitaxy'' as a novel kinetic pathway toward the
synthesis of non-equilibrium structures and materials [1, 2]. The discovery
of subsurfactant growth is of broad fundamental- and paramount practical
interest, particularly within the context of doping functional materials.
Secondly, we have successfully applied this conceptual advance to alleviate
a major bottleneck problem in spintronics, namely how to fabricate dilute
magnetic semiconductors with ferromagnetic ordering temperatures that exceed
room temperature by a comfortable margin while minimizing the structural
disorder and inhomogeneities that are intrinsic to high doping levels. Here,
we demonstrate that controlled Mn doping of Ge via subsurfactant epitaxy
produces ferromagnetic ordering temperatures well above room temperature at
doping levels that are at least 20 times lower than those typically invoked
in other fabrication techniques. Detailed comparison between samples grown
by conventional MBE [3-5], and samples grown via the subsurfactant procedure
[2] indicates the vastly superior structure-property relationship of the
latter. Subsurfactant epitaxy thus stands as a new and powerful avenue
toward superior dopant control in dilute magnetic semiconductors and
potentially other semiconductor applications that require doping levels far
above the thermodynamic solubility limit. Work done in collaboration with M.
Chisholm, L.C. Feldman, A.P. Li, J.R. Thompson, C. Zeng, and Z.Y. Zhang.
Funded by NSF-DMR-0306239. ORNL is managed by UT-Battelle, LLC, for the U.S.
DOE under constract No. DE-AC-5-00OR22725
[1] W. Zhu et al., Phys. Rev. Lett. 93, 126102 (2004).
[2] C. Zeng et al., submitted
[3] A.P. Li et al, Appl. Phys. Lett. 86, 152507 (2005)
[4] A.P. Li et al., Phys. Rev. B 72, 195205 (2005)
[5] Y.D. Park et al., Science 295, 651 (2002)
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.MAR.K12.1