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An experimental condensed matter physicist who, with Gene Dresselhaus and Charles Kittel, studied cyclotron resonance in silicon and germanium. Their 1955 work used single crystals near 4 K, light modulation and circularly polarized microwaves. Changing the orientation revealed direction-dependent band effective masses of electrons and electron holes, allowing measurements to reconstruct the shapes of constant-energy surfaces near the edges of energy bands.^[ref]

Gene Dresselhaus, Arthur F. Kip and Charles Kittel used cyclotron resonance to investigate electrons and holes in silicon and germanium crystals. Their 1955 measurements near 4 kelvin combined light modulation with circularly polarized microwaves and changes in the crystal orientation relative to the magnetic field. The directional dependence of the resonance revealed anisotropic carrier effective mass values and the shape of constant-energy surfaces near the edges of the electronic band structure. The experiment turns the orbital motion of charge carriers into a probe of electronic band structure.^[ref]

A carrier in a locally parabolic isotropic band obeys $m^{\ast }\dot{\mathbf{v}}=q\mathbf{v}\times \mathbf{B}$, soIlluminate a high-mobility crystal with a transverse alternating electric field, sweep a calibrated static magnetic field at known microwave or far-infrared frequency, and detect resonant absorbed power. Cooling lengthens the relaxation time; resolving the resonance generally needs ${\omega }_c\tau \gg 1$. Varying field direction measures band anisotropy, while circular polarization distinguishes the two senses of rotation for opposite carrier charges. This is orbital motion rather than electron spin resonance.

The classic silicon/germanium measurements used single crystals near $4\mathrm{K}$, light modulation and circularly polarized microwaves, with directional scans to infer anisotropic carrier-energy surfaces.^[ref] Carrier generation, calibration, scattering linewidth and inhomogeneity must be separated from a genuine mass shift.

In a general band the cyclotron mass is an orbit property, $m_c={\hslash }^2(\partial A_k/\partial E)/(2\pi )$ for the appropriate field-normal orbit. It need not equal every component of the band-curvature mass tensor. For an ellipsoidal parabolic band with field along a principal $z$ direction it is $\sqrt{m_x{m}_y}$. Thus a single resonance does not determine a whole effective-mass tensor without angular information.