Solution4JT+TW - Solutions of Problem set # 4 PHYS 361...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Solutions of Problem set # 4 PHYS 361 (Solid State Physics), Autumn 2009 1. Surface plasmon vs thin-film plasmon (a) Think about the new position of e- : x = x + u ( x ), the total number of electrons n s dx D in a strip of | dx D | is does not change after they move to a new area | dx D | : n e ( x ) dx D , where D is some length in y direction. Thus n e ( x ) = n s dx dx = n s 1+ qu cos( qx ) n s (1- qu cos( qx )). However there are compensating uniform background charges with density n s , therefore the total charge density is the difference between the above two: n s ( x ) = e n s- e n e ( x ) = eqn s u cos( qx ). There are several other ways doing this. (b) The potential of line segment dx of charge density n s ( x ) at a point with distance r to the axis of the line is d ( r ) = 2 ln r r , where r is some reference point of the potential and = n s ( x ) dx . Therefore ( x ) = R dx n s ( x ) 2 ln r x- x = en s u 2 cos( qx ) (c) the potential energy density is...
View Full Document

Page1 / 2

Solution4JT+TW - Solutions of Problem set # 4 PHYS 361...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online