Effects of the vacancy and doping on the electronic and magnetic characteristics of ZrSe2 monolayer: A first-principles investigation

Highlights: • V_1Zr (V_1Zr+1Se) defected ZrSe₂ monolayer is magnetic metal with moment 1.756 (1.295) µ_B. • V_1Se (V_1Zr+2Se) defected ZrSe₂ monolayer is nonmagnetic metal (semiconductor). • Cr- (Mo-) doped ZrSe₂ monolayer is magnetic metal with moment 2.482 (2.130) µ_B. • Mn- (Tc-, Re-) doped ZrSe₂ monolayer is magnetic semiconductor with moment 3.000 (2.999, 2.999) µ_B. • W-doped ZrSe₂ monolayer is magnetic half-metal with moment 2.000 µ_B and useable in spintronics. Based on the first-principles under the framework of density functional theory, we report the studies of vacancy defects and substitution doping on the electronic and magnetic characteristics of ZrSe₂ monolayer (ZrSe₂-ML). The results reveal that the non-magnetic semiconductor (SC) material ZrSe₂ has magnetic metal behavior by producing one Zr vacancy (V_1Zr) as well as one Zr and one Se di-vacancy (V_1Zr+1Se), the net moments are 1.756 and 1.295 ${\mu }_B$, and both originate from the Se atoms around the vacancies. The one Se vacancy (V_1Se) system exhibits the metal behavior, while the one Zr and two Se tri-vacancy (V_1Zr+2Se) system still maintains the characteristics of a non-magnetic SC. In addition, a transition metal (TM) atom X is used to replace one Zr atom in the non-magnetic SC material ZrSe₂, which can also induce magnetism or has metallic behavior. The Cr-, Mn-, Mo-, Tc-, W- and Re-doped systems exhibit the magnetic behavior with moments are 2.482, 3.000, 2.130, 2.999, 2.000, 2.999 ${\mu }_B$, respectively. The moments are proportional to the number of unpaired electrons remaining on the d orbitals of TM atoms. These systems have metallic characteristic of Cr- and Mo-doped. The Mn-, Tc- and Re-doped systems still maintain SC characteristic. In particular, the W-doped ZrSe₂-ML is half-metal. The calculated values show that under the condition of Se-rich, it is energetically favorable and relatively easy to dope TM atom into ZrSe₂-ML.