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Graduate Lecture Series 29 June – 3 July, 2009 Prof Ngee-Pong Chang Lecture 4 Electron Spin.

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Presentation on theme: "Graduate Lecture Series 29 June – 3 July, 2009 Prof Ngee-Pong Chang Lecture 4 Electron Spin."— Presentation transcript:

1 Graduate Lecture Series 29 June – 3 July, 2009 Prof Ngee-Pong Chang Lecture 4 Electron Spin

2 George Uhlenbeck 1900 - 1988

3 S. Goudsmit 1902 - 1978

4 Pieter Zeeman 1865 - 1943

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6 Photo taken by Zeeman of the splitting of the spectral lines in intense magnetic field. Reported on Saturday, October 31, 1896 at the meeting of the Royal Netherlands Academy of Arts and Sciences in Amsterdam, where these results were communicated by Kamerlingh Onnes. The next Monday, Lorentz called Zeeman in his office and presented him with an explanation of his observations, based on Lorentz' theory of electromagnetic radiation.Royal Netherlands Academy of Arts and SciencesAmsterdamelectromagnetic radiation

7 Hendrik A Lorentz 1853 - 1928

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9 Relationship between Magnetic Moment and Orbital Angular Momentum

10 Larmor Precession Zeeman Effect

11 Photo taken by Zeeman of the splitting of the spectral lines in intense magnetic field. Reported on Saturday, October 31, 1896 at the meeting of the Royal Netherlands Academy of Arts and Sciences in Amsterdam, where these results were communicated by Kamerlingh Onnes. The next Monday, Lorentz called Zeeman in his office and presented him with an explanation of his observations, based on Lorentz' theory of electromagnetic radiation.Royal Netherlands Academy of Arts and SciencesAmsterdamelectromagnetic radiation Anomalous Zeeman effect

12 Anomalous Zeeman Effect

13 Classical radius of the electron

14 Classical picture of electron spin !!!!! Compton wavelength Of the electron

15 Paul Ehrenfest 1880 - 1933

16 G.E. Uhlenbeck and S. Goudsmit, Naturwissenschaften 47 (1925) 953. A subsequent publication by the same authors, Nature 117 (1926) 264, is followed by a very interesting postscript by N. Bohr. See: http://www.lorentz.leidenuniv.nl/histo ry/spin/goudsmit.html

17 Ralph Kronig 1904 - 1995

18 Wolfgang Pauli 1900 - 1958

19 Pauli & Bohr & a spinning top

20 g – factor of the electron

21 Llewellyn H. Thomas 1903-1992 Thomas Precession of electron spin as a general relativity effect

22 Note to Goudsmit by L.H. Thomas Mar 25, 1926

23 I think you and Uhlenbeck have been very lucky to get your spinning electron published talked about before Pauli heard of it. It appears that more than a year ago Kronig believed in the spinning electron and worked out something; the first person he showed it to was Pauli. Pauli ridiculed the whole thing so much that the first person became also the last and no one else heard anything of it. Which all goes to show that the infallibility of the Deity does not extend to his self-styled vicar on earth.

24 Wolfgang Pauli 1900 - 1958

25 Denotes electron wave function with spin up Denotes electron wave function with spin down Pauli Spinor Wave Function

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27 Pauli Spin Matrices Group Properties

28 Spin Eigenfunctions

29 Measured Spin: Relation to Pauli Spin Wave Function Normalization Condition

30 Spin pointing in other than z-direction

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32 Precession of Electron Spin B-field in z-direction

33 Precession of Electron Spin

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37 Rotating the Electron Elementary Particles and the Laws of Physics: the 1986 Dirac Memorial Lectures by Richard Feynman, Steven Weinberg

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39 Why does the spin precess when there is No applied B field ?

40 Origin of Spin-Orbit Coupling Electron moving in a static E field sees a magnetic field, B : Electron spin precesses around this B field according to the magnetic moment interaction

41 Electron orbiting around nucleus In electron rest frame, nucleus orbiting around electron

42 Why does the spin precess when there is No applied B field ? Electron sees a B-field when it moves in a Voltage gate Origin of the Rashba term for spin-orbit coupling

43 Spintronics berlin lecture michaeli hulsen spin-fet Slide 9.

44 Spintronics berlin lecture michaeli hulsen spin-fet Slide 11.

45 Spintronics berlin lecture michaeli hulsen spin-fet Slide 22.

46 Spintronics berlin lecture michaeli hulsen spin-fet Slide 12.

47 Spintronics Datta-Das Spin Field Effect Transistor Precession controlled by Voltage gate Das Sarma RMP v76 00323 (2004) fig. 1

48 Das Sarma American Scientist v89, 516 (2001), Fig 3

49 Spintronics ferro insulator Ferromagnetic tunneling Das Sarma RMP v76 2004 00323, fig. 2

50 Das Sarma American Scientist v89, 516 (2001), Fig 7

51 Spintronics Solar Cell Datta-Das device Das Sarma American Scientist v89, 516 (2001), Fig 5

52 Das Sarma American Scientist v89, 516 (2001), Fig 2

53 Spin injection from a ferromagnet (F) into a normal metal (N) Das Sarma RMP v76 2004 00323, fig. 4

54 Spintronics spin injection accumulator detection Das Sarma RMP v76 2004 00323, fig. 5

55 Spintronics berlin lecture michaeli hulsen spin-fet Slide 10.

56 Spintronics berlin lecture michaeli hulsen spin-fet


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