Ultrahigh-Strain Phase Transitions and Electronic Switching in One-Dimensional Beryllium

Recent advances in low-dimensional materials have highlighted systems with stimulus-responsive behavior, paving the way for applications in smart nanodevices, sensors, and adaptive technologies. Here, using first-principles calculations, we report a systematic study of two one-dimensional allotropes of beryllium─a laterally staggered double-chain (Be-ribbon) and a single linear chain (Be-chain). Phonon spectra and ab initio molecular dynamics confirm the dynamic and finite-temperature kinetic stabilities of both phases. The Be-ribbon sustains an ultrahigh fracture strain (∼151%) and undergoes a strain-driven structural transition into the higher-energy Be-chain. We identify a critical tensile strain of 57% that separates reversible and irreversible behavior: below this threshold, the ribbon spontaneously recovers on unloading, whereas beyond it, the ribbon irreversibly converts to the chain. Hole injection induces a similar ribbon-to-chain transformation, providing a carrier-mediated switching pathway. Electronic-structure analysis reveals a distinctive conductor–semiconductor–conductor–semiconductor sequence during stretching, enabling reversible modulation of the conductive properties. Bond-order and charge-density analyses elucidate the atomistic mechanism for both mechanically and electronically induced transitions. These results highlight exceptional stretchability, controllable phase switching, and tunable electronic properties in one-dimensional beryllium, underscoring its potential for flexible electronics and programmable nanosystems.