Condensed Matter & Surface Sciences

COLLOQUIUM

 

 

 

Nitin Samarth

 

Penn State University

 

 

Spin Control in Magnetic Semiconductor Heterostructures

 

 

Magnetic semiconductor heterostructures provide an interesting playground for probing and manipulating spin interactions between extended electronic states and localized magnetic moments [1].  We provide an overview of recent experiments wherein we use a variety of techniques to engineer spin interactions in heterostructures derived from magnetic semiconductors such as (Ga,Mn)As and (Zn,Mn)Se.  Specific examples include:


the use of submicron lithography to tailor the Curie temperature of

   (Ga,Mn)As heterostructure devices by altering defect diffusion

   pathways [2]; 
* the exchange biasing of (Ga,Mn)As epilayers via antiferromagnetic

   overlayers [3];
* the opto-electronic tuning of coherent electron spin precession from GHz

   to near-THz frequencies in magnetic semiconductor quantum wells [4].

1. A. H. MacDonald, P. Schiffer, N. Samarth, Nature (Materials) 4, 195 (2005). 
2. K. F. Eid et al., Appl. Phys. Lett86, art. no. 152505 (2005).
3. K. F. Eid et al, Appl. Phys. Lett. 85, 1556 (2004).
4. R. C. Myers et al, Phys. Rev. B. (Rapid Comm.) 72, art. no. 041302 (2005).

 

 

 

Thursday, September 15, 2005

4:10 p.m. -- Walter Lecture Hall 245