arXiv subjects

David J. Hilton

Publications and source records attributed to David J. Hilton.

3 recordsLinked to original sources

arXiv2026

Broadband Terahertz Time-domain Spectroscopy of Quantum Materials in a Dilution Refrigerator

We have constructed a terahertz time domain spectroscopy system using a Bluefors dilution refrigerator with a 7 T split-coil magnet. Using a gallium arsenide single quantum well sample, terahertz waveforms were measured at 145 mK in a magnetic field range from 0 to 6 Tesla to measure cyclotron resonance. Effective mass is found to be $0.073 m_{e}$, which is larger than the commonly accepted bulk value of $0.068 m_{e}$.

cond-mat.other↗

arXiv2017

Generalized Elliott-Yafet spin-relaxation time for arbitrary spin mixing

We extend our recent result for the spin-relaxation time due to acoustic electron-phonon scattering in degenerate bands with spin mixing [New J. Phys. 18, 023012 (2015)] to include interactions with optical phonons, and present a numerical evaluation of the spin-relaxation time for intraband hole-phonon scattering in the heavy-hole (HH) bands of bulk GaAs. Comparing our computed spin-relaxation times to the conventional Elliott-Yafet result quantitatively demonstrates that the latter underestimates the spin-relaxation time because it does not correctly describe how electron-phonon interactions change the (vector) spin expectation value of the single-particle states. We show that the conventional Elliott-Yafet spin relaxation time is a special case of our result for weak spin mixing.

cond-mat.mtrl-sci↗

arXiv2010

Ultrafast Hole-Spin Dynamics in Optically Excited Bulk GaA

We present experimental and theoretical results on hole-spin dynamics in bulk GaAs after ultrafast optical excitation. The experimental differential transmission are compared with a dynamical calculation of the momentum-resolved hole distributions, which includes the carrier-carrier, carrier-phonon and carrier-impurity interaction at the level of Boltzmann scattering integrals. We obtain good agreement with the experimentally determined hole-spin relaxation times, but point out that depending on how the spin-polarization dynamics is extracted, deviations from an exponential decay at short times occur. We also study theoretically the behavior of the spin-relaxation for heavily p-doped GaAs at low temperatures.

cond-mat.mtrl-sci↗