Electronic properties of single and double napped carbon nanocones Felipe Azevedo Gomes, Valdir Barbosa Bezerra, Jonas Romero Fonseca de Lima and Fernando Jorge Sampaio Moraes Eur. Phys. J. B, 92 2 (2019) 41 Published online: 18 February 2019 DOI: 10.1140/epjb/e2019-90258-0