Magneto-optical properties of InSb for terahertz applications

TL;DR

This study investigates the magneto-optical properties of InSb crystals using terahertz spectroscopy, revealing large Kerr effects and tunable spectral responses promising for terahertz nonreciprocal devices.

Contribution

It provides detailed spectroscopic characterization of InSb's magneto-optical permittivity and demonstrates tunability of the spectral response through doping levels.

Findings

Large Kerr rotation up to 20 degrees at room temperature

Spectral response tunable via n-doping levels

Consistent modeling with Drude-Lorentz theory and Hall measurements

Abstract

Magneto-optical permittivity tensor spectra of undoped InSb, n-doped and p-doped InSb crystals were determined using the terahertz time-domain spectroscopy (THz-TDS) and the Fourier transform far-infrared spectroscopy (far-FTIR). A Huge polar magneto-optical (MO) Kerr-effect (up to 20 degrees in rotation) and a simultaneous plasmonic behavior observed at low magnetic field (0.4 T) and room temperature are promising for terahertz nonreciprocal applications. We demonstrate the possibility of adjusting the the spectral rage with huge MO by increase in n-doping of InSb. Spectral response is modeled using generalized magneto-optical Drude-Lorentz theory, giving us precise values of free carrier mobility, density and effective mass consistent with electric Hall effect measurement.