New materials are crucial for development of new technologies. To address challenges in energy, security, healthcare, and other areas, a range of new materials are urgently needed. For example, with the continued downscaling of electronic devices, silicon and its related technologies need to be replaced by new materials and new technologies. Computation has become an important approach in studies of materials for advanced technologies and will play an increasing role in design of new functional materials. First principles methods based on density functional theory, in particular, have unprecedented predicting power because they do not require experimental input and all physical quantities are computed self-consistently by solving quantum mechanical equations. It is the state-of-the-art approach for investigating properties of new materials and for designing new functional materials.

Using first-principles method as a tool, we investigate physical properties and phenomena of various materials and predict new materials which are of importance to future technologies. Some systems of current interest include spintronic and magnetic materials such as dilute magnetic semiconductors and related magnetism in non-magnetic systems, topological insulators, materials for memory and data storage, i.e., giant magnetoresistance, tunneling magnetic junction, and ferroelectric memory materials and systems, low dimensional materials such as graphene, phosphorene, transition metal dichalcogenides, and other two-dimensional materials, interfaces of different materials. Most of our studies are carried out in close collaboration with experimentalists.

materials prediction

Fig. (left) Calculated band structure of C-doped Bi2Se3. Note the opening of the Dirac gap and position of Fermi level (at 0 eV) – remain in the bulk gap. (right) Dependence of spin moment (per dopant) and Dirac gap on doping concentration (given in terms of average distance between dopands). See L Shen, et al. PRL 110, 016403 (2013) for details. 

To speed up the process of materials discovery and deployment, the materials Genomic approach has been developed rapidly, and begins to impact materials research and development. Taking advantages of extensive local research activities on 2D materials, we are working towards a Genome for 2D materials. High throughput first-principles calculations are carried out to investigate and analyze physical properties of various 2D materials in a systematic approach. The project is in collaboration with the Materials Project in Lawrence Berkeley National Lab.

Selected Publications

[1] J. R. Yuan, Y. Q. Cai, L. Shen, Y. Xiao, J. C. Ren, A. Z. Wang, Y. P. Feng, and X. H. Yan, One-dimensional thermoelectrics induced by Rashba spin-orbit coupling in two-dimensional BiSb monolayer, Nano Energy, 52, 163-170 (2018).

[2] L. Xu, M. Yang, L. Shen, J. Zhou, T. Zhu, and Y. P. Feng, Large valley splitting in monolayer WS2 by proximity coupling to an insulating antiferromagnetic substrate, Physical Review B, 97 (4), 041405(R), (10 January 2018).

[3] M. Yang, Y. Z. Luo, M. G. Zeng, L. Shen, Y. H. Lu, J. Zhou, S. J. Wang, I. K. Sou, and Y. P. FengPressure induced topological phase transition in layered Bi2S3, Phys. Chem. Chem. Phys., 19 (43), 29372-29380 (2017).

[4] L. Shen, M. G. Zeng, Y. H. Lu, M. Yang, and Y. P. Feng, Simultaneous Magnetic and Charge Doping of Topological Insulators with Carbon, Phys. Rev. Lett. 111, 23 (2013).

[5] H. Pan, J. B. Yi, L. Shen, R. Q. Wu, J. H. Yang, J. Y. Lin, Y. P. Feng, J. Ding, L. H. Van, and J. H. Yin, Room-temperature Ferromagnetism in Carbon-doped ZnO, Phys. Rev. Lett. 99, 12 (2007).