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# Fred Walker <walkerfj@ornl.gov>
# requesting 9 days, at minimum=6 days
# beamline 33ID, Crystal truncation rod characterization of thin-film STO on silicon
# instrument 33ID-D kappa
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# top:/home/www/beamtime-requests/req01016.txt
# UNICAT Member Beam Time Request  #1016
# created Tue Aug 15 14:48:36 CDT 2006
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apsrun:
	2006-03

beamline:
	33ID

collaboration:
	Yes

collaborator_Paul:
	ON

contact:
	walkerfj@ornl.gov

days:
	9

description:
	We will characterize the structure of thin-film SrTiO3 grown commensurately on silicon as a function of electrical boundary conditions.  The idea is to characterize the polarization of the film by varying the electrical boundary conditions from film to film.  For example, out-of-plane polarization is strongly supressed when either layer bounding the SrTiO3 thin film is insulating.  In this case, the depolarization field is large and the polarization is suppressed.  Conversely, adding a metallic top layer should allow a spontaneous, out-of-plane polarization to develop in the film.  The sign and magnitude of this polarization should be dependent on details of the electrical structure of the metallic overlayer, like density of states and work function (see Reiner et al. Phys Stat Solidi 241, 2287 2004).  We will test this thesis by measuring silicon crystal truncation rods at locations in reciprocal space where the intensity is most sensitive to ionic displacements in the SrTiO3 that result in polarization.   We will perform this measurement on a set of previously-grown, epitaxial films in vacuum using the kappa or Huber diffractometer on 34ID or 33BM.  We will use the method of Paul Fenter (CCD) and Specht et al. (wide open detector slit) to quantitatively measure the CTR intensity of specular and off-specular CTRs.

equipment_required:
	Beryllium dome, CCD detector.

experiment:
	Crystal truncation rod characterization of thin-film STO on silicon

foreign_nationals:
	

hazards:
	Vacuum.

instrument:
	33ID-D kappa

instrument_other:
	

minimumdays:
	6

name:
	Fred Walker

nonmembers:
	James Reiner, Yale
Charles Ahn, Yale

submit:
	Submit

unacceptable_dates:
	Nov. 23-26, 2006, 9 days may be split into two sessions.

z34ID_details:
	


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