## Theoretical Condensed Matter Physics

### Arun Bansil

Professor

PhD Harvard University, 1974

(617) 373-2923

bansil@neu.edu

### Research Summary

The recent research interests of Professor Bansil have focused on questions concerning the electronic structure and spectroscopy of high-Tc superconductors, topological insulators, nanosystems, and other complex materials. Professor Bansil’s group has developed and implemented the theoretical methodology for carrying out first-principles calculations of spectral intensities relevant for angle-resolved photoemission, scanning tunneling microscopy/spectroscopy, inelastic x-ray scattering, magnetic and non-magnetic Compton scattering, positron-annihilation angular correlation, among other spectroscopies in systems of the complexity of the high-Tc’s. Theoretical approaches based on the local-density approximation as well as techniques for going beyond this framework to incorporate effects such as strong electron correlations, superconductivity and phonons have been developed to obtain comprehensive spectroscopic modeling schemes. We are also considering how effects of substitutions and dopants on the electronic states can be treated realistically in wide classes of materials. These investigations have yielded, for example, important new insights into the existence of Fermi surfaces, the nature of electronic states near the Fermi energy, as well as the mechanism of superconductivity in the high-Tc’s. We have recently predicted successfully a number of new topological insulator materials through first-principles modeling. Professor Bansil’s research effort involves extensive collaborations with groups within and outside the United States.

### Recent Publications:

Topological Phase Transition and Texture Inversion in a Tunable Topological Insulator: Xu, Su-Yang, Xia, Y., Wray, L. A., Jia, S., Meier, F., Dil, J. H., Osterwalder, J., Slomski, B., Bansil, A., Lin, H., Cava, R. J., Hasan, M. Z.,

Science 332, 560-564 (2011).

Imaging Doped Holes in a Cuprate Superconductor with High-Resolution Compton Scattering: Sakurai, Y., Itou, M., Barbiellini, B., Mijnarends, P. E., Markiewicz, R. S., Kaprzyk, S., Gillet, J-M, Wakimoto, S., Fujita, M., Basak, S., Wang, Yung Jui, Al-Sawai, W., Lin, H., Bansil, A., Yamada, K.,

Science 332, 698 (2011).

A topological insulator surface under strong Coulomb, magnetic and disorder perturbations: Wray, L. Andrew, Xu, Su-Yang, Xia, Yuqi, Hsieh, David, Fedorov, Alexei V., Hor, Yew San, Cava, Robert J., Bansil, Arun, Lin, Hsin, Hasan, M. Zahid,

Nature Physics 7, 32 (2011).

Direct Observation of Broken Time-Reversal Symmetry on the Surface of a Magnetically Doped Topological Insulator: Okada, Yoshinori, Dhital, Chetan, Zhou, Wenwen, Huemiller, Erik D., Lin, Hsin, Basak, S., Bansil, A., Huang, Y. -B., Ding, H., Wang, Z., Wilson, Stephen D., Madhavan, V.,

Physical Review Letters 106, 206805 (2011).

Renormalization of f levels away from the Fermi energy in electron excitation spectroscopies: Density-functional results for Nd_{2-x}Ce_{x}CuO_{4}: Jarlborg, T., Barbiellini, B., Lin, H., Markiewicz, R. S., Bansil, A.,

Physical Review B 84, 045109 (2011).

### Related Links:

Unraveling the Mysteries of High Temperature Superconductors

Doughnuts, Soccer Balls and Exotic Topological Insulators