Graduate Lecture Series29 June – 3 July, 2009

Prof Ngee-Pong Chang

Lecture 4

Electron Spin

George Uhlenbeck1900 - 1988

S. Goudsmit1902 - 1978

Pieter Zeeman1865 - 1943

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.

Hendrik A Lorentz1853 - 1928

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.

Anomalous Zeeman effect

Anomalous Zeeman Effect

Classical radius of the electron

Classical picture of electron spin

!!!!!

Compton wavelengthOf the electron

Paul Ehrenfest1880 - 1933

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/history/spin/goudsmit.html

Ralph Kronig1904 - 1995

Wolfgang Pauli1900 - 1958

Pauli & Bohr & a spinning top

g – factor of the electron

Llewellyn H. Thomas1903-1992

Thomas Precession of

electron spin as a general

relativity effect

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

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 Pauli1900 - 1958

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

NormalizationCondition

Spin pointing in other than z-direction

Spin pointing in other than z-direction

Precession of Electron Spin

B-field in z-direction

Precession of Electron Spin

Precession of Electron Spin

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 precesswhen there is No applied B field ?

Origin of Spin-Orbit CouplingElectron 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 precesswhen 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 v76 00323 (2004) fig. 1

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

Spintronics ferro insulator Ferromagnetic tunneling

Das Sarma RMP v76 2004 00323, fig. 2

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

Spintronics Solar CellDatta-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 v76 2004 00323, fig. 4

Spintronics spin injection accumulator detection

Das Sarma RMP v76 2004 00323, fig. 5

Spintronics berlin lecture michaeli hulsen spin-fet Slide 10.

Spintronics berlin lecture michaeli hulsen spin-fet