Research Projects

The arrangements of spins in a quantum material can be the conventional ferromagnetic, and antiferromagnetic one if only translation symmetry and both translation and time reversal (TR) symmetries, respectively, are protected. Very recently, an unconventional magnetism namely, altermagnetism (AM) has been found where spins are related by complex crystalline symmetries combining translation, rotation and TR thus extending the domain of quantum magnetism. The observed altermagnetic band-splitting is a one order of magnitude larger and thus the AMs are expected to generate giant responses due to TR symmetry breaking than conventional ferromagnet. Simultaneously, AMs have symmetry protected net vanishing magnetization which makes it promising candidate for thermoelectric device applications. The key reason for large interest in recent days on altermagnetic materials is the strong splitting of spin-polarized electronic bands in non-relativistic limit on the altermagnetic background. This leads to the unique properties such as momentum dependent band splitting, anisotropic spin-split Fermi surfaces. Topological Berry phase physics is a consequence of relativistic spin-orbit coupling effects whereas unconventional topological properties in AMs arise from non-relativistic origin. Kramers spin degeneracy has been lifted due to altermagnetic phase without net magnetization and inversion-symmetry breaking. This opens possibilities for exploration of new topological Berry phases in AMs. Additionally, canting the direction of N´eel vector in AMs changes the crystal symmetry of system and interplay between them allows for the realization of a wide variety of topological phases through Berry curvature design. This opens possibility of engineering topological bands in AMs which significantly influences its responses. Altermagnets enables novel applications for magneto-transport originating from Berry curvature formalism such as anomalous Hall effect (AHE) and its thermoelectric counterpart anomalous Nernst effect (ANE). Therefore, in the current proposal, we choose altermagnetic materials for investigating AHE and ANE. Therefore in this proposal, our goal is twofold, (i) engineer topological bands and properties in altermagnetic materials, then (ii) investigate AHE and ANE responses. To realise this proposal, we use methodology cascading of three different approaches. Theoretical framework will consists of ab- initio density functional theoretical calculations and in-house transport code with tight binding Hamiltonian. We believe that, our proposal will guide to make simple energy converter for thermo- electric devices based on AHE and ANE using altermagnetic topological materials with enhance efficiency. In the long run, our results will enrich the understanding of unconventional topological Berry phases and dissipationless quantum transport in AMs which has a strong impact across diverse areas of research and technology for low energy electronic transport.