  Twin-field quantum key distribution (TF-QKD) protocol and its variants, e.g.
phase-matching (PM) QKD and TF-QKD based on sending or not sending, are highly
attractive since they are able to overcome the well-known rate-loss limit for
QKD protocols without repeater: $R=O(\eta)$ with $\eta$ standing for the
channel transmittance. However, all these protocols require active phase
randomization and post-selection that play an essential role together in their
security proof. Counterintuitively, we find that in TF-QKD, beating the
rate-loss limit is still possible even if phase randomization and
post-selection in the coding mode are both removed, which means our final
secure key rate $R=O(\sqrt{\eta})$. Furthermore, our protocol is more feasible
in practice and more promising according to its higher final key rate in the
valid distance. Our security proof counters collective attack and can also
counter coherent attack in asymptotical case
