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Abstract Layer Hall effect (LHE), initially discovered in the magnetic topological insulator MnBi2Te4 film, expands the Hall effect family and opens a promising avenue for layertronics applications. In this study, we present an innovative ferroelectric bilayer model to attain a tunable quantum anomalous layer Hall effect (QALHE). This model comprises two ferromagnetic orbital-active Dirac monolayers stacked antiferromagnetically, accompanied by out-of-plane electric polarization. The interplay between the layer-locked Berry curvature monopoles and the intrinsic out-of-plane electric polarization leads to layer-polarized near-quantized anomalous Hall conductance. Using first-principles calculations, we have identified a promising material for this model, namely FeS bilayer. Our calculations demonstrate that the intrinsic out-of-plane electric polarization in the Bernal-stacked FeS bilayer can induce QALHE by regulating the layer-locked Berry curvature of FeS monolayers. Importantly, the intrinsic electric field can be reversed through interlayer sliding. The discovery of ferroelectrically modulated QALHE paves the way for the integrability and non-volatility of layertronics, offering exciting prospects for future applications.

To study the bond performance of ultra-high performance concrete (UHPC) and steel bar after freeze-thaw cycles (FTCs), the eccentric pull-out test of 10 groups of reinforced UHPC bond specimens, the compressive test of 24 cube specimens and the splitting tensile test of 24 cube specimens were carried out. The degradation of UHPC mechanical properties and bond performance of UHPC and steel bar after FTCs were studied. The influence of UHPC strength, cover thickness, and bond length on bond strength after FTCs was analyzed. The relationship between mechanical and bond properties is established by using compressive strength and average bond strength as indexes. A formula for calculating average bond strength of UHPC after FTCs was developed. The results show that the elastic modulus loss, compressive strength loss, and splitting tensile strength loss after FTCs increase slowly at first and then rapidly. With the increase of FTCs, the relationship between dynamic elastic modulus and compressive strength, compressive strength, and splitting tensile strength showed strong linear characteristics. UHPC strength is an important factor affecting the average bond strength after FTCs, followed by the cover thickness. After 600 freeze-thaw cycles, the failure mode of the UHPC bond specimen changed. The compressive strength and the average bond strength show a strong linear relationship in the process of 900 FTCs. The average bond strength between UHPC and steel bar decreased by 13.76 ∼ 17.23 % after 900 freeze-thaw cycles.

Abstract Sliding ferroelectricity (SFE) found in two-dimensional (2D) van der Waals (vdW) materials, such as BN and transition-metal dichalcogenides bilayers, opens an avenue for 2D ferroelectric materials. Multiferroic coupling in 2D SFE materials brings us an alternative concept for spintronic memory devices. In this study, using first-principles calculations, we demonstrate that MnSe multilayers constructed by the recently-synthesized MnSe monolayer have large sliding-driven reversible out-of-plane electric polarization (~10.6 pC m−1) and moderate interlayer sliding barriers superior to the existing 2D SFE materials. Interestingly, the intrinsic electric polarization is accompanied by nonzero net magnetic moments which are also switchable via lateral interlayer sliding. Additionally, both SFE and magnetoelectric coupling can be effectively regulated by external strain and/or hole doping. Our findings suggest the potential of MnSe multilayers in 2D multiferroic and spintronic applications.