02-Marche_Delta
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Les conditions de raccord sont donc :<br />
⎧<br />
⎨ ψ I (0) = ψ II (0)<br />
Explicitement :<br />
⎩<br />
− ¯h2<br />
2m [ψ′ II(0) − ψ ′ I(0)] + aψ I (0) = 0<br />
− ık¯h2<br />
2m<br />
A + B = C<br />
(C − A + B) + a(A + B) = 0<br />
Exprimons B et C comme fonctions de A :<br />
où<br />
Solution :<br />
ψ(x) =<br />
( ık¯h<br />
2<br />
)−1<br />
B = A<br />
am − 1<br />
( ) −1<br />
am<br />
C = A<br />
ık¯h 2 + 1<br />
{<br />
ψ in (x) + ψ r (x) x < 0<br />
ψ t (x) x > 0 ,<br />
ψ in (x) def<br />
= Ae ıkx<br />
ψ r (x) def<br />
= A<br />
( ık¯h<br />
2<br />
am − 1 )−1<br />
e −ıkx<br />
( ) −1 am<br />
ψ t (x) def<br />
= A<br />
ık¯h 2 + 1 e ıkx<br />
2.1.4 Coecients de transmission et de réexion<br />
Courant incident :<br />
Courant transmis :<br />
Courant rééchi :<br />
Coecient de transmission :<br />
j in = |A| 2 ¯hk<br />
m<br />
) −1<br />
j t = |A| 2 ¯hk<br />
(1 + ma2<br />
m 2¯h 2 E<br />
( )−1<br />
j r = |A| 2 ¯hk<br />
1 + 2¯h2 E<br />
m ma 2<br />
T def<br />
= j t<br />
j in<br />
=<br />
(1 + ma2<br />
2¯h 2 E<br />
) −1<br />
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