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

Abstract

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 $0.073m_e$, which is larger than the commonly accepted bulk value of $0.068m_e$.

10 pages, 5 figures