## Theoretical Condensed Matter Physics

### Arun Bansil

University Distinguished Professor

Director, Advanced Scientific Computation Center (ASCC)

PhD Harvard University, 1974

(617) 373-2923

ar.bansil@neu.edu

### Research Summary

Bansil’s research interests are focused on questions concerning the electronic structure and spectroscopy of high-Tc superconductors, topological insulators, two-dimensional atomically thin films beyond graphene, nanosystems, and other novel materials. 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 a wide range of complex systems. Theoretical approaches based on the density functional theory as well as techniques for going beyond this framework to incorporate effects of strong electron correlations, superconductivity and phonons have been developed to obtain comprehensive spectroscopic modeling schemes, including methods for a realistic treatment of effects of substitutions and dopants on the electronic states. These investigations have yielded new insights into the existence of Fermi surfaces, the nature of electronic states near the Fermi energy, spin-orbit coupling effects and 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. Bansil’s research effort involves extensive collaborations with groups within and outside the United States.

### Recent Publications:

Y. Zhang, T-R. Chang, B. Zhou, Y-T. Cui, H. Yan, Z. Liu, F. Schmitt, J. Lee, R. Moore, Y. Chen, H. Lin, H-T. Jeng, S-K. Mo, Z. Hussain, A. Bansil and Z-X. Shen: “Direct observation of the transition from indirect to direct bandgap in atomically thin epitaxial MoSe_{2},” Nature Nanotech. 9, 111 (2014).

Y. He, Y. Yin, M. Zech, A. Soumyanarayanan, M. M. Yee, T. Williams, M. C. Boyer, K. Chatterjee, W. D. Wise, I. Zeljkovic, T. Kondo, T. Takeuchi, H. Ikuta, P. Mistark, R. S. Markiewicz, A. Bansil, S. Sachdev, E. W. Hudson, and J. E. Hoffman: “Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor,” Science 9, 608 (2014).

F-C. Chuang, L-Z. Yao, Z-Q. Huang, Y-T. Liu, C-H. Hsu, T. Das, H. Lin & A. Bansil: “Prediction of Large-Gap 2D Topological Insulators of Group III Bilayers with Bi,” Nano Lett. 14, 2505 (2014).

M. Neupane, S-Y. Xu, R. Sankar, N. Alidoust, G. Bian, C. Liu, I. Belopolski, T-R. Chang, H-T. Jeng, H. Lin, A. Bansil, F. Chou & M. Z. Hasan: “Observation of a three-dimensional topological Dirac semimetal phase in high-mobility Cd_{3}As_{2},” Nature Commun. 5, 3786 (2014).

R. S. Markiewicz, J. J. Rehr & A. Bansil: “Lattice Model of Resonant Inelastic X-Ray Scattering in Metals: Relation of Strong Core Hole to X-Ray Edge Singularity,” Phys. Rev. Lett. 112, 237401 (2014).

I. Zeljkovic, Y. Okada, C-Y. Huang, R. Sankar, D. Walkup, W. Zhou, M. Serbyn, F. Chou, W-F. Tsai, H. Lin, A. Bansil, L. Fu, M. Z. Hasan and V. Madhavan: “Mapping the unconventional orbital texture in topological crystalline insulators,” Nature Physics 10, 572 (2014).

G. Gupta, H. Lin, A. Bansil, M. B. A. Jalil, C-Y. Huang, W-F. Tsaiand G. Liang: “Y-Shape Spin-Separator for two-dimensional Group-IV Nanoribbons based on Quantum Spin Hall Effect,” App. Phys. Lett. 104, 032410 (2014).

A. Vargas, S. Basak, F. Liu, B. Wang, E. Panaitescu, H. Lin, R. Markiewicz, A. Bansil, and S. Kar: “The Changing Colors of a Quantum-Confined Topological Insulator,” ACS Nano 8, 1222 (2014).

T. Saari, C-Y. Huang, J. Nieminen, W-F. Tsai, H. Lin, and A. Bansil: “Electrically tunable localized tunneling channels in silicene nanoribbons,” App. Phys. Lett. 104, 173104 (2014).

M. Neupane, A. Richardella, J. Sánchez-Barriga, S-Y. Xu, N. Alidoust, I. Belopolski, C. Liu, G. Bian, D. Zhang, D. Marchenko, A. Varykhalov, O. Rader, M. Leandersson, T. Balasubramanian, T-R. Chang, H-T. Jeng, S. Basak, H. Lin, A. Bansil, N. Samarth and M. Z. Hasan: “Observation of quantum-tunnelling-modulated spin texture in ultrathin topological insulator Bi_{2}Se_{3} films,” Nature Commun. 5, 3841 (2014).

### Related Links:

Unraveling the Mysteries of High Temperature Superconductors

Doughnuts, Soccer Balls and Exotic Topological Insulators