Twisted helical armchair graphene nanoribbons: mechanical and electronic propertiesRajesh Thakur, P. K. Ahluwalia, Ashok Kumar, Munish Sharma and Raman SharmaEur. Phys. J. B, 94 5 (2021) 99DOI: https://doi.org/10.1140/epjb/s10051-021-00102-1