Abstract
This work presents the results of first principles calculations of the electronic and magnetic properties of the compound SnTe and GeTe in zinc blende (ZB) and rock salt (RS) structures, doped with 3d transition metal V, Cr, and Mn. The present study, initiated from the viewpoint of potential application in spintronics, is motivated by our earlier work involving these two compounds, where the doping was limited to the Sn and Ge sublattices. In view of some discrepancies between our calculated results and the available experimental data, in this work we have examined the effect of the Te-sublattice doping. The case of Mn-doping, where the previous results of calculations seemed to differ most from the experimentally available data, is examined further by looking at the effect of Mn atoms partially occupying interstitial sites as well. From the standpoint of potential application in spintronics, we look for half-metallic (HM) states and tabulate their properties in both rock salt and zinc blende structures. ZB structure is found to be more conducive to HM state in general. Among the binary compounds we identify several HM candidates: VGe, VSn, MnGe, MnSn and MnTe at their equilibrium volumes and all in ZB structure. Estimates of the Curie temperature for the ferromagnetic compounds including the half-metals are presented. It is shown that despite the ferromagnetic (FM) nature of the Mn-Mn interaction for the Te-doped case, a simultaneous doping of both Ge(Sn)- and Te-sublattice with Mn atoms would leave the material predominantly antiferromagnetic (AFM).
Highlights
A commonly occurring structure for many of the IV-VI semiconductors is the rock-salt (RS) structure
GeTe thin films doped with 3d transition metals (TM) have received considerable attentions as well, with most of them showing ferromagnetic behavior.[7,8,9,10,11]
For Ge1 xMnxTe thin films with x=0.51, Curie temperature of 140 K was reported,[7] while for Ge1 xCrxTe with x ≤0.1 some reported Curie temperatures were higher than 100 K.12
Summary
A commonly occurring structure for many of the IV-VI semiconductors is the rock-salt (RS) structure. 1312 K its structure is found to be NiAs-type hexagonal.[17] In recent publications we have presented ab inito theoretical studies of the magnetic properties of transition metal (TM) doped GeTe and SnTe (TM = V, Cr, Mn), with TM concentration in Ge(Sn)-sublattice being 25% and above. While theoretical calculations showed AFM Mn-Mn interaction for the Mn-doped compounds, some experiments suggested FM behavior. In view of the above theoretical and experimental results we have decided to complement the previous studies[18,19,20] by considering the magnetic effects of TM-doping of the Te-sublattice. Our previous studies[18,19,20] involving ZB structure and the present study involving TM-doping of the Te-sublattice are based on the expectation that fabrication of such materials, in spite of their positive formation energies, may become possible with advances in materials processing and growth. Readers interested in specific results, e.g. density of states, band structure, bulk moduli, exchange interactions and Curie temperatures for particular compounds, are advised to contact the corresponding author.[30]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
