Magnetic and Electronic Switch in Metal Intercalated Two-Dimensional GeP$_3$

TL;DR

This study uses first-principles calculations to demonstrate that intercalating Cr atoms in 2D GeP$_3$ can switch its magnetic state from antiferromagnetic to ferromagnetic under strain, also inducing metallic and spin-polarized electronic channels.

Contribution

It reveals a new method to control magnetic and electronic properties in 2D materials through atomic intercalation and mechanical strain.

Findings

Cr intercalation stabilizes in the vdW gap of GeP$_3$ bilayers.

Mechanical strain can switch magnetic order from antiferromagnetic to ferromagnetic.

Cr doped GeP$_3$ systems exhibit strain-induced spin-polarized metallic channels.

Abstract

Intercalation of foreign atoms in two dimensional hosts has been considered a quite promising route in order to engineer the electronic, and magnetic properties in 2D plataforms. In the present study, we performed a first-principles theoretical investigation of the energetic stability, and the magnetic/electronic properties of 2D GeP$_3$ doped by Cr atoms. Our total energy results reveal the formation of thermodynamically stable Cr doped GeP$_3$ bilayer [(GeP$_3$)$_{BL}$], characterized by interstitial Cr atoms lying in the van der Waals (vdW) gap between (GeP$_3$)$_{BL}$ [(GeP$_3$)$_{BL}^{Cr}$]. We show that the ground state row-wise antiferromagnetic (RW-AFM) phase of (GeP$_3$)$_{BL}^{Cr}$ can be tuned to a ferromagnetic (FM) configuration upon compressive mechanical strain ($\varepsilon$), Cr$^{\uparrow \downarrow} \xrightarrow{\varepsilon}$Cr$^{\uparrow \uparrow}$. By considering its stacked counterparts, (GeP$_3$)$_{BL}^{Cr}$/(GeP$_3$)$_{BL}^{Cr}$, and (GeP$_3$)$_{BL}^{Cr}$/Cr/(GeP$_3$)$_{BL}^{Cr}$, we found that such a magnetic tuning is dictated by a combination of intralayer and interlayer couplings, where the RW-AFM phase change to layer-by-layer FM (Cr$^{\uparrow \uparrow}$//Cr$^{\uparrow \uparrow}$) and AFM (Cr$^{\uparrow \uparrow}$/Cr$^{\downarrow \downarrow}$/Cr$^{\uparrow \uparrow}$) phases, respectively. Further electronic band structure calculations show that these Cr doped systems are metallic, characterized by the emergence of strain induced spin polarized channels at the Fermi level. These findings reveal that the atomic intercalation, indeed, offers a new set of degree of freedom for the design and control the magnetic/electronic properties in 2D systems.