Mn4Al11: A Half-Semimetal Candidate with Anomalous Electronic Behaviors

TL;DR

This study investigates Mn4Al11, revealing its potential as a half-semimetal with unique electronic and magnetic properties, characterized by low carrier density, magnetic transition, and anomalous transport and optical behaviors.

Contribution

The paper introduces Mn4Al11 as a new half-semimetal candidate with ferrimagnetic order, supported by experimental and theoretical analysis.

Findings

Low carrier concentration and magnetic transition near 68 K.

Anomalous transport and optical behaviors at low temperatures.

Electronic structure calculations support half-semimetallic nature.

Abstract

Half-semimetals, characterized by their spin-polarized electronic states, hold significant promise for spintronic applications but remain scarce due to stringent electronic and magnetic criteria. Through a combination of transport measurements and optical spectroscopy, we investigated the intermetallic compound Mn4Al11, which features an exceptionally low carrier concentration and undergoes a magnetic phase transition near 68 K. Transport measurements reveal anomalies that deviate from typical metallic behavior at low temperatures. Optical spectroscopy indicates a small, nearly frequency-independent optical conductivity in the far-infrared region, with spectral weight decreasing as the temperature drops from 300 K to 50 K. These behaviors suggest a temperaturedependent carrier density and significant scattering of charge carriers. Combining experimental findings with calculated electronic band structures, we propose that Mn4Al11 is a novel half-semimetal candidate exhibiting a ferrimagnetic ground state.