The Search Of Lossless Metals And Discovery Of Hyper-gap Materials

For the development of computing technology,the high-throughput computational search method based on the first-principles density functional theory began to play an important role in materials science,and can quickly find new materials with outstand-ing properties through large-scale computations.Optical materials are vital for many optoelectronic fields such as optoelectronic display,surface plasmon polariton,nonlin-ear optics,pulse transmission,etc.The study of new optical materials are increasingly becoming a research area of concern,and the high-throughput computational search can greatly promote the research process of optical materials and clarify the research direction of subsequent experiments.Metallic materials that have the same low light absorption as transparent insulators and can conduct both electrons and photons are of great importance to optoelectronics.We conducted the first high-throughput search for such”lossless”metals in inorganic materials and found 381 candidates.We have further processed these candidates by defining the figure of merit and analyze these candidates by the real-space conductive connectivity.Through the feedback of literatures,we summarize the actual situation of these materials and discuss the differences between calculations and experiments.Based on the high-throughput computational search,we propose future research directions of lossless metals,including high-symmetry oxides,intercalated two-dimensional mate-rials,and compressing these false-metal candidates under high pressures into eventual lossless metals.We analyzed the performance of the candidate LiTi₂O₄as a lossless metal by the ellipsometry measurements,demonstrating the potential possibilities of lossless metals.Starting from the lossless metal,we propose a new class of optical materials—hyper-gap materials.As narrow-band crystals,the materials can be equally transpar-ent in some energy range above the ordinary band gap,opening fundamentally new windows for linear and nonlinear optics.These hyper-gap lossless windows possess optical properties that break the limits of ordinary optical materials,including giant material dispersion,direct phase-matching without birefringence,and lossless negative permittivity.We perform an exhaustive high-throughput computational search among inorganic materials and find over 400 such hyper-gap optical materials.We analyze the optical properties of these candidates through the optical calculations,including the specific distribution of the three optical properties in these materials.Hyper-gap mate-rials have the opportunity to transform optical science and technology with unexplored material opportunities.