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

George Uhlenbeck

S. Goudsmit

Pieter Zeeman

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

Hendrik A Lorentz

Relationship between Magnetic Moment and Orbital Angular Momentum

Larmor Precession Zeeman Effect

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

Anomalous Zeeman Effect

Classical radius of the electron

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

Paul Ehrenfest

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: ry/spin/goudsmit.html

Ralph Kronig

Wolfgang Pauli

Pauli & Bohr & a spinning top

g – factor of the electron

Llewellyn H. Thomas Thomas Precession of electron spin as a general relativity effect

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

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.

Wolfgang Pauli

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

Pauli Spin Matrices Group Properties

Spin Eigenfunctions

Measured Spin: Relation to Pauli Spin Wave Function Normalization Condition

Spin pointing in other than z-direction

Precession of Electron Spin B-field in z-direction

Precession of Electron Spin

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

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

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

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

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

Spintronics berlin lecture michaeli hulsen spin-fet Slide 9.

Spintronics berlin lecture michaeli hulsen spin-fet Slide 11.

Spintronics berlin lecture michaeli hulsen spin-fet Slide 22.

Spintronics berlin lecture michaeli hulsen spin-fet Slide 12.

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

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

Spintronics ferro insulator Ferromagnetic tunneling Das Sarma RMP v , fig. 2

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

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

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

Spin injection from a ferromagnet (F) into a normal metal (N) Das Sarma RMP v , fig. 4

Spintronics spin injection accumulator detection Das Sarma RMP v , fig. 5

Spintronics berlin lecture michaeli hulsen spin-fet Slide 10.

Spintronics berlin lecture michaeli hulsen spin-fet