Bound states of Dirac fermions in the presence of a Fermi velocity modulation Ullah Kalim, Jun-Tong Ren, Sha-Sha Ke, Yuan Feng and Hai-Feng Lü EPL, 144 5 (2023) 50001 Published online: 20 December 2023 DOI: 10.1209/0295-5075/ad129f