The low-energy electronic structure of SnSe single crystals measured by high-resolution angle-resolved photoelectron spectroscopy: the multi-valley peak energy band and the similar linear dispersion of graphene; and on this basis, it can be understood from the microscopic mechanism and seek for high thermoelectricity. The "pudding-mould" model of value materials.

The study found that the low-energy electronic structure of SnSe combines a unique "multivalley" band with linear dispersion similar to graphene (Figure 1). The former can greatly enhance the Seebeck coefficient of the material, which leads to a decrease in the effective mass of the electrons in the material and thus an effective enhancement of the electrical conductivity of the material. The combination of the two leads to a great value of the thermoelectric properties of the SnSe material. Enhanced. Based on this, the study proposes a "pudding-mould" model that can understand and find high-quality thermoelectric materials from the perspective of microcosmic mechanism. This is also the first time that people can understand the uniqueness of SnSe from the perspective of electronic structure. Thermoelectric properties. In addition, through the introduction of controllable SnSe2 impurity states and point dislocations, we have realized the effective regulation of the carrier concentration in SnSe materials on the basis of maintaining the original basic physical properties, in order to use the "defect engineering" in the future. "This mature and effective means to synthesize and improve high-efficiency thermoelectric materials has opened up new theoretical directions and technological basis."

Wang Zhen, Department of Physics, Zhejiang University and Dr. Fan Congcong, Ph.D., Shanghai Institute of Microsystems, Chinese Academy of Sciences, co-authored the first author of the dissertation. Shen Dawei, a researcher of the Center for Excellence in Superconducting Electronic Research at the Chinese Academy of Sciences, and Zheng Yi, a researcher at the Physics Department of Zhejiang University, were co-authors of the paper. The work was supported by the project of the Fund's National Major Instruments (project approval number) and other projects.

(Original title: Shanghai Microsystems has made significant progress in the field of electronic structure of thermoelectric materials)