Low-Frequency Electronic Noise Spectroscopy of Quasi-2D van der Waals Antiferromagnetic Semiconductors

TL;DR

This study uses low-frequency noise spectroscopy to explore electronic fluctuations in quasi-2D antiferromagnetic FePS3, revealing unique temperature-dependent behaviors and phase transition signatures relevant for spintronic applications.

Contribution

It provides the first detailed noise analysis of FePS3, uncovering unusual Lorentzian features and temperature dependencies that differ from conventional semiconductor noise mechanisms.

Findings

Noise spectral density peaks near Neel temperature

Minimum noise at approximately 200 K due to competing effects

Unusual temperature and bias dependence of Lorentzian corner frequencies

Abstract

We investigated low-frequency current fluctuations, i.e. noise, in the quasi-two-dimensional (2D) van der Waals antiferromagnetic semiconductor FePS3 with the electronic bandgap of 1.5 eV. The electrical and noise characteristics of the p-type, highly resistive, thin films of FePS3 were measured at different temperatures. The noise spectral density was of the 1/f - type over most of the examined temperature range but revealed well-defined Lorentzian bulges, and increased strongly near the Neel temperature of 118 K (f is the frequency). Intriguingly, the noise spectral density attained its minimum at temperature T~200 K, which was attributed to an interplay of two opposite trends in noise scaling - one for semiconductors and another for materials with the phase transitions. The Lorentzian corner frequencies revealed unusual dependence on temperature and bias voltage, suggesting that their origin is different from the generation - recombination noise in conventional semiconductors. The obtained results are important for proposed applications of antiferromagnetic semiconductors in spintronic devices. They also attest to the power of the noise spectroscopy for monitoring various phase transitions.