Controlling magnetism of two-dimensional multiferroics by an external electric field provides special opportunities for both fundamental research and future development of low-cost electronic nanodevices. Here, we report a general scheme for realizing a magnetic phase transition in 2D type-I multiferroic systems through the reversal of ferroelectric polarization. Based on first-principles calculations, we demonstrate that a single-phase 2D multiferroic, namely, ${\mathrm{ReWCl}}_6$ monolayer, exhibits two different low-symmetric ($C_2$) phases with opposite in-plane electric polarization and different magnetic order. As a result, an antiferromagnetic-to-ferromagnetic phase transition can be realized by reversing the in-plane electric polarization through the application of an external electric field. These findings not only enrich the 2D multiferroic family, but also uncover a unique and general mechanism to control magnetism by electric field, thus stimulating experimental interest.

Pressure, a fundamental thermodynamic variable, can generate two essential effects on materials. First, pressure can create new high-pressure phases via modification of the potential energy surface. Second, pressure can produce new compounds with unconventional stoichiometries via modification of the compositional landscape. These new phases or compounds often exhibit exotic physical and chemical properties that are inaccessible at ambient pressure. Recent studies have established a broad scope for developing materials with specific desired properties under high pressure. Crystal structure prediction methods and first-principles calculations can be used to design materials and thus guide subsequent synthesis plans prior to any experimental work. A key example is the recent theory-initiated discovery of the record-breaking high-temperature superhydride superconductors H₃S and LaH₁₀ with critical temperatures of 200 K and 260 K, respectively. This work summarizes and discusses recent progress in the theory-oriented discovery of new materials under high pressure, including hydrogen-rich superconductors, high-energy-density materials, inorganic electrides, and noble gas compounds. The discovery of the considered compounds involved substantial theoretical contributions. We address future challenges facing the design of materials at high pressure and provide perspectives on research directions with significant potential for future discoveries.

Searching for experimentally feasible intrinsic quantum anomalous Hall (QAH) insulators is of great significance for dissipationless electronics applications. Here we predict, based on density functional theory (DFT), that four monolayer transition metal tri-bromides (VBr₃, FeBr₃, NiBr₃, and PdBr₃) are endowed with intrinsic half-metallicity and possess quantum anomalous Hall insulating phases. DFT+U calculations reveal that the VBr₃, NiBr₃, and PdBr₃ monolayers undergo nontrivial to Mott insulator transitions with increasing on-site Hubbard Coulomb interaction U at 0.5, 2 and 3 eV. The gap opening induced by the spin–orbit coupling drives the systems into the QAH state. The Curie temperatures of the VBr₃, NiBr₃, and PdBr₃ monolayers are ∼190, 100 and 110 K. Additionally, the calculated cleavage energies suggest that the freestanding VBr₃, FeBr₃, NiBr₃, and PdBr₃ monolayers can be easily produced by exfoliation using adhesive tape, which may stimulate experimental research interest to achieve QAH phases.