A Group-IV Ferromagnetic Semiconductor: Mn x Ge 1− x
Abstract
We report on the epitaxial growth of a group-IV ferromagnetic semiconductor, Mn x Ge 1− x , in which the Curie temperature is found to increase linearly with manganese (Mn) concentration from 25 to 116 kelvin. The p -type semiconducting character and hole-mediated exchange permit control of ferromagnetic order through application of a ±0.5-volt gate voltage, a value compatible with present microelectronic technology. Total-energy calculations within density-functional theory show that the magnetically ordered phase arises from a long-range ferromagnetic interaction that dominates a short-range antiferromagnetic interaction. Calculated spin interactions and percolation theory predict transition temperatures larger than measured, consistent with the observed suppression of magnetically active Mn atoms and hole concentration.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 25, 2002
- Source ID
- 10.1126/science.1066348
Entities
People
- A. T. Hanbicki
- Anna M. Wilson
- Berend T Jonker
- C. S. Hellberg
- G. Spanos
- J. E. Mattson
- J. M. Sullivan
- S. C. Erwin
- T. F. Ambrose
- Y. D. Park
Organizations
- United States Naval Research Laboratory