First principles design of Ohmic spin diodes based on quaternary Heusler compounds

TL;DR

This paper presents a first-principles design of Ohmic spin diodes using quaternary Heusler compounds, demonstrating their potential for room-temperature spintronic applications with linear I-V characteristics and high on/off ratios.

Contribution

The study introduces a novel first-principles approach to designing Ohmic spin diodes based on quaternary Heusler compounds, highlighting their suitability for room-temperature spintronics.

Findings

All four designed OSDs show linear I-V characteristics with zero threshold voltage.

The OSDs exhibit small leakage currents due to band overlap in SGS electrodes.

On/off current ratios range from 30 to 10^5.

Abstract

The Ohmic spin diode (OSD) is a recent concept in spintronics, which is based on half-metallic magnets (HMMs) and spin-gapless semiconductors (SGSs). Quaternary Heusler compounds offer a unique platform to realize the OSD for room temperature applications as these materials possess very high Curie temperatures as well as half-metallic and spin-gapless semiconducting behavior within the same family. Using state-of-the-art first-principles calculations combined with the non-equilibrium Green's function method we design four different OSDs based on half-metallic and spin-gapless semiconducting quaternary Heusler compounds. All four OSDs exhibit linear current-voltage ($I-V$) characteristics with zero threshold voltage $V_T$. We show that these OSDs possess a small leakage current, which stems from the overlap of the conduction and valence band edges of opposite spin channels around the Fermi level in the SGS electrodes. The obtained on/off current ratios vary between $30$ and $10^5$. Our results can pave the way for the experimental fabrication of the OSDs within the family of ordered quaternary Heusler compounds.