We use the Kubo formalism to calculate the transresistivity rho(21) fo
r carriers in coupled quantum wells in a large perpendicular magnetic
field B. We find that rho(21) is enhanced by approximately 50-100 time
s over that of the B = 0 case in the interplateau regions of the integ
er quantum Hall effect. The presence of both electron-electron interac
tions and Landau quantization results in (i) a twin-peaked structure o
f rho(21)(B) in the interplateau regions at low temperatures and (ii)
for the chemical potential at the center of a Landau level band, a pea
ked temperature dependence of rho(21)(T)/T-2.