We demonstrate that the sliding motion between two layers of the newly discovered ferroelectric and topologically trivial bismuth(Bi)monolayer[Nature 61767(2023)]can induce a sequence of topological phase transitions,...We demonstrate that the sliding motion between two layers of the newly discovered ferroelectric and topologically trivial bismuth(Bi)monolayer[Nature 61767(2023)]can induce a sequence of topological phase transitions,alternating between Z_(2)trivial and nontrivial states.The lateral shift,while preserving spatial symmetry,can switch the quantum spin Hall state on and of.The sliding-induced changes in out-of-plane atomic buckling,which are directly coupled to in-plane ferroelectricity,are shown to signifcantly modulate the band gap and drive the topological phase transitions.We map out the topological phase diagram and in-plane ferroelectricity with respect to sliding displacements.With appropriate sliding,the bismuth bilayer can transition into a nontrivial polar metal,exhibiting a pronounced shift current response arising from interband geometric quantities of electronic bands.Moreover,bilayer Bi supports a sliding-tunable nonlinear anomalous Hall response resulting from the geometric Berry curvature dipole.Confgurations that are Z_(2)nontrivial can generate drastically different transverse currents orthogonal to the external electric feld,as both the direction and magnitude of the Berry curvature dipole at the Fermi level are highly sensitive to the sliding displacement.Our results suggest that bilayer bismuth,with its ability to generate multiple types of geometric currents,ofers a versatile platform for power-efcient“Berry slidetronics”for multistate memory applications integrating both band topology and ferroelectricity.展开更多
This paper is concerned with the bifurcation properties on the line of discontinuity of planar piecewise smooth systems. The existence of equilibria and periodic solutions with sliding motion in a class of planar piec...This paper is concerned with the bifurcation properties on the line of discontinuity of planar piecewise smooth systems. The existence of equilibria and periodic solutions with sliding motion in a class of planar piecewise smooth systems with 3-parameters is investigated in this paper using the theory of differential inclu-sion and tools of Poincar′e maps.展开更多
Utilizing a nanogenerator to scavenge mechanical energy from our living environment is an effective method to solve the power source issue of portable electronics. We report a linear-grating hybridized electromagnetic...Utilizing a nanogenerator to scavenge mechanical energy from our living environment is an effective method to solve the power source issue of portable electronics. We report a linear-grating hybridized electromagnetic-triboelectric nanogenerator for scavenging the mechanical energy generated from sliding motions to sustainably power certain portable electronics. The hybridized nano- generator consists of a slider and a stator in the structural design, and possesses a 66-segment triboelectric nanogenerator （TENG） and a 9-segment electromagnetic generator （EMG） in the functional design. At a sliding acceleration of 20 m/s2 the hybridized nanogenerator can deliver maximum powers of 102.8 mW for the TENG at a loading resistance of 0.4 Mr2 and 103.3 mW for the EMG at a loading resistance of 6 kf2. With an optimal hybridized combination of the TENG with a transformer and the EMG with a power management circuit, a 10 mF capacitor can be easily charged to 2.8 V in 20 s. A packaged hybridized nanogenerator with a light weight of 140 g and small dimensions of 12 cm× 4 cm× 1.6 cm excels in scavenging low-frequency sliding energy to sustainably power portable electronics.展开更多
基金the supports from Westlake Education Foundationthe support provided by the National Natural Science Foundation of China(Grant No.12304049)。
文摘We demonstrate that the sliding motion between two layers of the newly discovered ferroelectric and topologically trivial bismuth(Bi)monolayer[Nature 61767(2023)]can induce a sequence of topological phase transitions,alternating between Z_(2)trivial and nontrivial states.The lateral shift,while preserving spatial symmetry,can switch the quantum spin Hall state on and of.The sliding-induced changes in out-of-plane atomic buckling,which are directly coupled to in-plane ferroelectricity,are shown to signifcantly modulate the band gap and drive the topological phase transitions.We map out the topological phase diagram and in-plane ferroelectricity with respect to sliding displacements.With appropriate sliding,the bismuth bilayer can transition into a nontrivial polar metal,exhibiting a pronounced shift current response arising from interband geometric quantities of electronic bands.Moreover,bilayer Bi supports a sliding-tunable nonlinear anomalous Hall response resulting from the geometric Berry curvature dipole.Confgurations that are Z_(2)nontrivial can generate drastically different transverse currents orthogonal to the external electric feld,as both the direction and magnitude of the Berry curvature dipole at the Fermi level are highly sensitive to the sliding displacement.Our results suggest that bilayer bismuth,with its ability to generate multiple types of geometric currents,ofers a versatile platform for power-efcient“Berry slidetronics”for multistate memory applications integrating both band topology and ferroelectricity.
文摘This paper is concerned with the bifurcation properties on the line of discontinuity of planar piecewise smooth systems. The existence of equilibria and periodic solutions with sliding motion in a class of planar piecewise smooth systems with 3-parameters is investigated in this paper using the theory of differential inclu-sion and tools of Poincar′e maps.
基金This work was supported by Beijing Natural Science Foundation （No. 2154059）, the China Postdoctoral Science Foundation （No. 2015M570988）, the National Natural Science Foundation of China （Nos. 51472055 and 61404034）, the 2015 Annual Cooperative Project between Chinese Academy of Sdences and Industrial Technology Research Institute （No. CAS-ITRI201501）, and the ＂thousands talents＂ program for the pioneer researcher and his innovation team, China.
文摘Utilizing a nanogenerator to scavenge mechanical energy from our living environment is an effective method to solve the power source issue of portable electronics. We report a linear-grating hybridized electromagnetic-triboelectric nanogenerator for scavenging the mechanical energy generated from sliding motions to sustainably power certain portable electronics. The hybridized nano- generator consists of a slider and a stator in the structural design, and possesses a 66-segment triboelectric nanogenerator （TENG） and a 9-segment electromagnetic generator （EMG） in the functional design. At a sliding acceleration of 20 m/s2 the hybridized nanogenerator can deliver maximum powers of 102.8 mW for the TENG at a loading resistance of 0.4 Mr2 and 103.3 mW for the EMG at a loading resistance of 6 kf2. With an optimal hybridized combination of the TENG with a transformer and the EMG with a power management circuit, a 10 mF capacitor can be easily charged to 2.8 V in 20 s. A packaged hybridized nanogenerator with a light weight of 140 g and small dimensions of 12 cm× 4 cm× 1.6 cm excels in scavenging low-frequency sliding energy to sustainably power portable electronics.
