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8/28/2015PHY 752 Fall 2015 -- Lecture 21 PHY 752 Solid State Physics 11-11:50 AM MWF Olin 103 Plan for Lecture 2: Reading: Continue reading Chapter 1 in.

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Presentation on theme: "8/28/2015PHY 752 Fall 2015 -- Lecture 21 PHY 752 Solid State Physics 11-11:50 AM MWF Olin 103 Plan for Lecture 2: Reading: Continue reading Chapter 1 in."— Presentation transcript:

1 8/28/2015PHY 752 Fall 2015 -- Lecture 21 PHY 752 Solid State Physics 11-11:50 AM MWF Olin 103 Plan for Lecture 2: Reading: Continue reading Chapter 1 in GGGPP; Electrons in one-dimensional periodic potentials 1.Review of Bloch’s Theorem 2.Kronig-Penny model potential from the viewpoint of scattering or tunneling

2 8/28/2015PHY 752 Fall 2015 -- Lecture 22

3 8/28/2015PHY 752 Fall 2015 -- Lecture 23

4 8/28/2015PHY 752 Fall 2015 -- Lecture 24 Li 2 SnO 3

5 8/28/2015PHY 752 Fall 2015 -- Lecture 25 Li 2 SnS 3

6 8/28/2015PHY 752 Fall 2015 -- Lecture 26 Bloch theorem:

7 8/28/2015PHY 752 Fall 2015 -- Lecture 27 Eigenvalue solutions to Kronig-Penny model

8 8/28/2015PHY 752 Fall 2015 -- Lecture 28

9 8/28/2015PHY 752 Fall 2015 -- Lecture 29 From wavefunction matching conditions: Condition for non-trivial solution: Simplified result:

10 8/28/2015PHY 752 Fall 2015 -- Lecture 210

11 8/28/2015PHY 752 Fall 2015 -- Lecture 211 v v Forbidden states f

12 8/28/2015PHY 752 Fall 2015 -- Lecture 212 f ka/  Band gap

13 8/28/2015PHY 752 Fall 2015 -- Lecture 213 Treatment of same problem in terms of transmission and reflection from a periodic barrier. First consider a single barrier: Matrix for determining coefficients:

14 8/28/2015PHY 752 Fall 2015 -- Lecture 214 Matching conditions for wavefunction coefficients:

15 8/28/2015PHY 752 Fall 2015 -- Lecture 215 Solving for transfer matrix elements:

16 8/28/2015PHY 752 Fall 2015 -- Lecture 216 Transmittance

17 8/28/2015PHY 752 Fall 2015 -- Lecture 217 After some algebra:

18 8/28/2015PHY 752 Fall 2015 -- Lecture 218 Electron transmission through a one-dimensional periodic barrier Because of Bloch theorem:

19 8/28/2015PHY 752 Fall 2015 -- Lecture 219 Bloch theorem & transmission coefficients: Condition for solution:


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