From unusual mechanical response to Dirac-like behavior: Topology-driven evolution of physical properties in holey borophenes

Borophene is distinguished from most two-dimensional materials by its electron-deficient multicenter bonding, which enables exceptional structural tolerance to systematic vacancy formation. Exploiting this unique characteristic, we systematically design six holey borophene allotropes through systematic vacancy patterning on a common parent lattice, establishing a topological vacancy-concentration series. First-principles calculations, combined with machine-learning interatomic potentials, demonstrate that pattern-guided vacancy engineering provides an effective means of tailoring the electronic, thermal, and mechanical properties of borophene. Notably, the evolving vacancy topology gives rise to Dirac-like electronic band dispersion, enables a broad modulation of room-temperature (300 K) lattice thermal conductivity, spanning 2.61–15.40 W m -1 K -1 along and 2.60–16.42 W m -1 K -1 along , and dynamically tunes the Poisson’s ratio from negative and near-zero to positive values. More importantly, our results demonstrate that the unique structural flexibility of borophene allows systematic defect introduction without structural collapse, providing a practical route for engineering multifunctional two-dimensional materials. These findings establish patterned vacancy engineering as a general design strategy for developing borophene-based materials with tunable electronic, thermal, and mechanical functionalities.