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Stripe Ordering in the Cuprates
Leland HarrigerHomework Project for Solid State IIInstructor: Elbio DagottoPhysics Dept., University of Tennessee at KnoxvilleSpring 2009
What is Stripe Ordering?
A periodic modulation of charge and spin.
Modulation of charge and spin are related by the phase boundary.
Result: Spin periodicity is twice that of charge periodicity
Why does Stripe Ordering Occur?
The Distance that Separates.
)(1
)(
copper
holesxnh
)(
)(1
copperN
holenh
a
LN
2
x
aLc 2
x
aLm
42 CuOSrLa xx
Scattering Basics (Preclude to testing for stripe ordering.)
if kkQ
Magnetic Scattering
0L
222
2
c
L
b
K
a
HQ
KH
ba
dQ
2
)0,,( HHQ
2
1H
Reciprocal Space of CuO4 in the Presence of Stripe Ordering. Big Circles are nuclear
Bragg peaks. Small plusses are
magnetic Bragg peaks. Other symbols are
incommensurate spreading of peaks due to stripe ordering.
Estimate of δ as a function of x.
x
aLc 2
x
aLm
xc ~
2c
m
Neutron Scattering
The triple axis spectrometer is very versatile for measurements of bulk solids.
Q-scans (ie: momentum transfer) Both elastic and inelastic Typically performed at a
fixed energy transfer. Energy Scans
Set E=0 for elastic scans Typically performed at a
fixed Q.
What Proof do We have of Stripe Ordering?
What does Stripe Ordering Mean for Superconductivity?
References
[1] J. Orenstein, et. al Science 288, 468 (2000) J. Tranquada, et. al. Nature 375, 561 J. Tranquada, et. al. Phys. Rev. Lett. 78, 338 S. Chi, et. al. Phys. Rev. Lett. 102 107005 Ph. Bourges, et. al. Physica C 424, 45 Yamada K. et. al. Phys. Rev. B 57 6165