Coexistence of topological nontrivial and spin-gapless semiconducting behavior in MnPO4: A composite quantum compound

Composite quantum compounds (CQC) are a classic example of quantum materials, which host more than one apparently distinct quantum phenomenon in physics. Magnetism, topological superconductivity, Rashba physics, etc. are a few such quantum phenomenon, which are ubiquitously observed in several functional materials and can coexist in CQCs. In this paper, we use ab initio calculations to predict the coexistence of two incompatible phenomena, namely topologically nontrivial Weyl semimetal and spin-gapless semiconducting (SGS) behavior, in a single crystalline system. SGS belongs to a special class of spintronics material, which exhibits a unique band structure involving a semiconducting state for one spin channel and a gapless state for the other. We report such a SGS behavior in conjunction with the topologically nontrivial multi-Weyl fermions in MnPO4. Interestingly, theseWeyl nodes are located very close to the Fermi level with the minimal trivial band density. A drumhead-like surface state originating from a nodal loop around Y point in the Brillouin zone is observed. A large value of the simulated anomalous Hall conductivity (1265 Omega(-1)cm(-1)) indirectly reflects the topological nontrivial behavior of this compound. Such co-existent quantum phenomena are not common in condensed matter systems and hence it opens up a fertile ground to explore and achieve newer functional materials.

Automated summary

This study uses ab initio calculations to predict the coexistence of topologically nontrivial Weyl semimetal and spin-gapless semiconducting behavior in a single crystalline system, and observes such phenomena in MnPO4. The coexistence of these quantum phenomena, not common in condensed matter systems, provides a fertile ground for exploring and achieving newer functional materials.