Defect-Induced Bound States in the Continuum Band of Nanoribbons

Bound states in the continuum (BICs) can be induced by structural defects or impurities [1]. These bound states have numerous applications in devices as solid-state lasers [2], sensors [3], and narrowband filters [4]. In this work, we report a detailed study of BICs in a finite nanoribbon with defects. This study was carried out by means of the Kubo-Greenwood formula and tight-binding Hamiltonian, as well as a real-space renormalization plus convolution method [5]. The calculated density of states reveals the presence of a BIC, whose localization degree was quantified by the participation ratio [6]. In addition, significant changes in the electronic transport and localization are found when a small second-neighbor hopping integral between the impurities and neighboring atoms is considered. Moreover, this study shows the sensibility of such BICs to short-range hopping integrals. Finally, BICs in finite second-neighbor square lattices have also been analyzed by using a new convolution theorem [7].<br/><br/>This work has been partially supported by projects UNAM-IN112522, UNAM-IN110823 and CF-2023-I-830. Computations were performed at Miztli of DGTIC-UNAM.<br/><br/>[1] I. Piquero-Zulaica, <i>et. al</i>, <i>Rev. Mod. </i><i>Phys</i>. <b>94</b> (4), 045008 (2022).<br/>[2] A. Kodigala, T. Lepetit, Q. Gu, B. Bahari, Y. Fainman, and B. Kanté, <i>Nature</i> <b>541</b>, 196 (2017).<br/>[3] A. A. Yanik, <i>et. al</i>, <i>Proc. </i><i>Natl. Acad. Sci. USA</i> <b>108</b>, 11784 (2011).<br/>[4] J. M. Foley, S. M. Young, and J. D. Phillips, <i>Phys. Rev. B</i> <b>89</b>, 165111 (2014).<br/>[5] V. Sánchez and C. Wang, <i>Phys. Rev. B</i> <b>70</b>, 144807 (2004).<br/>[6] V. Sanchez, F. Sanchez and C. Wang, <i>Phys. Status Solidi</i> <i>B</i> <b>256</b>, 1800369 (2019).<br/>[7] F. Sanchez, V. Sanchez and C. Wang, <i>Eur. Phys. J. B</i> <b>91</b>, 132 (2018).