Magneto-optical response of magnetic semiconductors EuCd2X2 (X= P, As, Sb)

TL;DR

This paper investigates the magnetic and electronic properties of EuCd2X2 (X= P, As, Sb) semiconductors, revealing how their band gaps respond to chemical substitution and magnetic fields, with potential implications for spintronic applications.

Contribution

It provides the first systematic study of the band gap evolution and magnetic response of EuCd2X2 semiconductors across different X elements.

Findings

Band gaps decrease from 1.23 eV to 0.52 eV across the series.

Magnetic fields cause a non-monotonic decrease in band gaps.

All compounds remain semiconductors up to 16 T.

Abstract

In this study, we identify EuCd2X2 (for X = P, As, Sb) as a series of magnetic semiconductors. We examine how the band gap of the series responds to X changing from phosphorus (P), to arsenic (As), and finally antimony (Sb). We characterize the samples using electronic transport and magnetization measurements. Based on infrared spectroscopy, we find that the band gap reduces progressively from 1.23 eV in EuCd2P2, to 0.77 eV in EuCd2As2, and finally 0.52 eV in EuCd2Sb2. In a magnetic field, all three systems show a strong response and their band gaps decrease at 4 K. This decrease is non-monotonic as we change X. It is strongest in the phosphorous compound and weakest in the antimony compound. For all the three compositions, EuCd2X2 remains a semiconductor up to the highest magnetic field applied (16 T).