The Origin of Localization in Ti-Doped Silicon

Intermediate band semiconductors hold the promise to significantly improve the efficiency of solar cells, but only if the impurity band is metallic. We apply our recently developed first principles method [1-4] to investigate the nature of localization in Ti-doped Si, a promising candidate for intermediate band solar cells. Our results show that, contrary to common belief, Anderson localization plays a more important role than Mott localization in the metal-insulator transition. Implications for the theory of intermediate band solar cells will be discussed.

[1] T. Berlijn, D. Volja, and W. Ku PRL 106, 077005 (2011)
[2] C. E. Ekuma, H. Terletska, K.-M. Tam, Z.-Y. Meng, J. Moreno, and M. Jarrell, PRB 89, 081107 (2014)
[3] Y. Zhang, H. Terletska, C. Moore, C. Ekuma, K.-M. Tam, T. Berlijn, W. Ku, J. Moreno, and M. Jarrell, PRB 92, 205111 (2015)
[4] Y. Zhang, R. Nelson, E. Siddiqui, K-M Tam, U. Yu, T. Berlijn, W. Ku, NS Vidhyadhiraja, J. Moreno, and M Jarrell, PRB 94, 224208 (2016)