The transport and thermoelectric properties together with annealing of the new layered Bi-chalcogenide LaOBiHgS_3 are studied. On the transport part, the insulating behavior of the as-grown sample is evidently depress...The transport and thermoelectric properties together with annealing of the new layered Bi-chalcogenide LaOBiHgS_3 are studied. On the transport part, the insulating behavior of the as-grown sample is evidently depressed by post annealing.A hump-like abnormality appears around 170 K. The thermoelectric performance of the sample is observably improved by the annealing, mainly because of the enhanced electrical conductance. The present results suggest that the physical properties of LaOBiHgS_3 are sensitive to post annealing and the possible micro adjustments that follow, indicating the layered Bi-chalcogenide family to be an ideal platform for designing novel functional materials.展开更多
Spontaneous polarization and bulk photovoltaic effect(BPVE)are two concomitant physical properties in ferroelectric materials.The flipping of ferroelectric order usually accompanies the switching of BPVE in all direct...Spontaneous polarization and bulk photovoltaic effect(BPVE)are two concomitant physical properties in ferroelectric materials.The flipping of ferroelectric order usually accompanies the switching of BPVE in all directions because both of them are reversed under the inversion symmetry.In this study,we report the non-synchronous BPVE in two-dimensional(2D)interlayer-sliding ferroelectric materials featuring unswitchable in-plane BPVE(light-induced photocurrent in the xy plane)and switchable out-of-plane BPVE(light-induced polarization along the z-direction).Symmetry analysis within the abstract bilayer crystal model and first-principles calculations validate these BPVE properties.It is because the positive and negative ferroelectric states caused by interlayer sliding are related by mirror symmetry which cannot flip all the BPVE tensor elements.This finding extends the understanding of the relationship between ferroelectricity and BPVE.On one hand,the switchable out-of-plane BPVE can be used to design switchable photoelectric devices.On the other hand,the in-plane BPVE is robust against the ferroelectric flipping,and the unswitchable character is beneficial to construct larger-scale photoelectric devices.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51572001,11404002,and 11404003)the ‘211 Project’ of Anhui University,China(Grant No.J01001319J10113190007)
文摘The transport and thermoelectric properties together with annealing of the new layered Bi-chalcogenide LaOBiHgS_3 are studied. On the transport part, the insulating behavior of the as-grown sample is evidently depressed by post annealing.A hump-like abnormality appears around 170 K. The thermoelectric performance of the sample is observably improved by the annealing, mainly because of the enhanced electrical conductance. The present results suggest that the physical properties of LaOBiHgS_3 are sensitive to post annealing and the possible micro adjustments that follow, indicating the layered Bi-chalcogenide family to be an ideal platform for designing novel functional materials.
基金This work is supported by the National Natural Science Foundation of China under No.11947212Natural Science Foundation of Anhui Province under No.110158162022+2 种基金in part by the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences Large-Scale Scientific Facility under Grant No.U1932156in part by the Natural Science Foundation of Anhui Province under Grant No.2008085QA29Y.G.and R.-C.X.acknowledge the startup foundation from USTC and AHU,respectively.
文摘Spontaneous polarization and bulk photovoltaic effect(BPVE)are two concomitant physical properties in ferroelectric materials.The flipping of ferroelectric order usually accompanies the switching of BPVE in all directions because both of them are reversed under the inversion symmetry.In this study,we report the non-synchronous BPVE in two-dimensional(2D)interlayer-sliding ferroelectric materials featuring unswitchable in-plane BPVE(light-induced photocurrent in the xy plane)and switchable out-of-plane BPVE(light-induced polarization along the z-direction).Symmetry analysis within the abstract bilayer crystal model and first-principles calculations validate these BPVE properties.It is because the positive and negative ferroelectric states caused by interlayer sliding are related by mirror symmetry which cannot flip all the BPVE tensor elements.This finding extends the understanding of the relationship between ferroelectricity and BPVE.On one hand,the switchable out-of-plane BPVE can be used to design switchable photoelectric devices.On the other hand,the in-plane BPVE is robust against the ferroelectric flipping,and the unswitchable character is beneficial to construct larger-scale photoelectric devices.
