Modification of ferromagnetism in semiconductors by molecular monolayers

Abstract

We report that adsorption of monolayers of organic molecules onto ferromagnetic semiconductor heterostructures can produce large changes in magnetic properties [1]. The digital-alloy heterostructures studied have 1/2 monolayer MnAs planes embedded in GaAs. We investigate effects on magnetic properties of self-assembly of various organic molecules onto the heterostructure surface. Depending on the molecular structure, the monolayers can either strengthen or suppress ferromagnetism. We attribute this chemical modulation of magnetic properties to electronic changes brought about by molecular binding to the semiconductor surface.

Robust Manipulation of Magnetism in Dilute Magnetic Semiconductor (Ga,Mn)As by Organic Molecules

“…A primary reason behind the scarcity may be the diffi culty of creating high-quality SAMs on III-V DMSs. One such work [ 26 ] demonstrated robust modifi cation of ferromagnetism in a semiconducting ferromagnet by adsorption of monolayers of alkylphosphonic acids on a GaAs cap layer via a phosphonate group. However, the material is a heterogeneous ½ monolayer MnAs buried below 5 nm of GaAs and only suppression of ferromagnetism is shown.…”

The Cooperative Molecular Field Effect

“…Effects on Magnetic and Superconducting Properties COMFE was also found to affect the magnetic properties of a MnGaAs-based transistor. [41] The adsorption of monolayers of organic molecules onto the surface of ferromagnetic semiconductor heterostructures produces large, robust changes in the magnetic properties of the system. The semiconductor material used has half a monolayer of zinc-blende MnAs embedded in low-temperature-grown GaAs, 50 beneath the surface.…”

Study of thickness variation, morphology, and magnetic properties of Permalloy on organic monolayers

“…2-7 Surface adsorption of organic monolayers influences the electronic properties and spin transport in semiconductors 8 and the magnetic properties of inorganic materials. 9 Deposition of different metals on selfassembled monolayers ͑SAMs͒ containing different organic functional groups ͑OFGs͒ has been a thoroughly studied process in the context of molecular electronics. The morphology of the deposited metals is influenced by the nature of the chemical interactions occurring at the interface of the terminal functional group of the SAM and the deposited metal.…”