Prof. Kumar started his research career in theory of disordered alloys and received his Ph.D. from University of Roorkee under the supervision of Prof. S.K. Joshi. In 1979 he was awarded the prestigious Alexander von Humboldt Fellowship in Germany where he worked on problems related to surfaces of metals and alloys. He returned to India in 1985 in Reactor Research Center (now Indira Gandhi Center for Atomic Research), Kalpakkam and worked in the area of quasicrystals – a hot topic at that time. He characterized the Penrose lattice and developed atomic models of decagonal phase of quasicrystals. Prof. Kumar has worked with several leading researchers around the world. He is the first person in India to have started work on Car-Parrinello method with Prof. R. Car soon after its development. This ab initio molecular dynamics method is now the most important development in the area of electronic structure of materials and it has led to the possibilities of designing materials at the atomistic level by computer simulations. Using this method Prof. Kumar has done pioneering work in the area of nanomaterials. He predicted silicon fullerenes from computer simulations and these have now been realized in laboratory in 100 mg quantity in Japan. Such examples are few where theoretical predictions led to experimental work. He has published more than 200 research papers/review articles/book chapters and edited 4 books. His work is now followed worldwide and is well cited (see https://scholar.google.co.in/citations?hl=en&user=Uq92p1kAAAAJ&view_op=l..., and www.researchgate.net/profile/Vijay_Kumar260).
Prof. Kumar made important contributions in the area of education also. He was invited to coordinate the Diploma Programme in Condensed Matter Physics at the ICTP Trieste, Italy – an institute of UNESCO and IAEA, in order to prepare bright students from developing countries for research. This programme became very successful. Prof. Kumar promoted computational materials science in India by organizing conferences. Prof. Kumar Co-organized the First National Conference on a new developing area of Materials Genome in 2013 in SNU. It aims to design materials using computational work. Prof. Kumar realized the importance of computational work quite early and proposed the formation of a subject group on Computer Aided Design of Materials in Materials Research Society of India (MRSI) in 1996 and served its first Chairman. Prof. Kumar was also President of Indian Physics Association (Kalpakkam Chapter) and there he also contributed to expose the school children to developments in science. Prof. Kumar was also instrumental in greatly contributing to the formation of Asian Consortium for Computational Materials Science (ACCMS) in 2000 and it has now become a well-established forum for researchers in Asia. He was given the first ACCMS Award for his scientific dedication and contributions to the formation of ACCMS. To promote education and research, Prof. Kumar has also established Dr. Vijay Kumar Foundation (Gurgaon) of which he is the Founder President.
Ab initio studies of nanomaterials including clusters, nanoparticles, nanowires, and nanotubes, 2D materials such as graphene, silicene, phosphorene, borophene, and related systems, surfaces of metals and semiconductors, energy materials and materials for opto-electronic applications, hard materials, laser materials such as YAG, segregation in materials, bulk metallic glasses and quasicrystals, DNA like inorganic materials.