Paper link:
/articles/s42254-022-00423-9
As a physical dimension and window to adjust the physical and chemical properties of materials, pressure brings colorful and unprecedented phenomena and results, which greatly promotes people's understanding of the special properties under compression conditions. It can not only test the technical parameters and theories that are difficult to obtain under conventional conditions, but also capture and reproduce the outstanding characteristics realized under high pressure under conventional pressure conditions. Although high-pressure technology has made a breakthrough in the characterization and research of material properties in the past century, the accurate measurement of material thermal conductivity under high pressure has always been a difficult problem in high-pressure research. By the end of last century, the measurement of thermal conductivity was still limited to a few GPa, which was far behind other technical representations in the same period by nearly two orders of magnitude. It greatly limits the research on heat conduction, thermal diffusion and thermal management of materials under high pressure, and restricts the understanding and development of thermal properties of materials. The big technical bottleneck breakthrough comes from the introduction of spectral measurement method, and the data of thermal conductivity exceeding 10 GPa was obtained only in the past 15 years. Because the authors of this paper mainly participated in the development and popularization of these technologies, they provided detailed technical details and application scenarios in this overview.
They summarized the research progress of high-pressure thermal conductivity in recent years, focusing on the research results of thermal conductivity of thermoelectric materials, mineral materials in the earth and semiconductor materials under high pressure, and summarized the behavior and physical mechanism of pressure changing the thermal conductivity of these materials, as well as the implicit and potential scientific significance. For thermoelectric materials, research shows that pressure can effectively adjust the thermoelectric figure of merit of thermoelectric materials. It is found that when the pressure reaches a certain critical value, the thermoelectric materials studied will undergo topological phase transition, which will lead to the enhancement of thermoelectric properties. These findings provide a new way to improve the thermoelectric properties of materials. For geoscience materials, they pointed out that by combining two optical characterization methods with theoretical calculation, we can explore the heat transport mechanism of deep minerals in the earth from many aspects, so as to understand the thermodynamic activities inside the earth. For many semiconductor materials, the study of thermal conductivity under high pressure mainly depends on theoretical calculation, and the thermal conductivity of semiconductor materials shows complex anisotropy, so the experimental technology needs to be further improved. Finally, the opportunities and challenges of thermal conductivity research under high pressure are prospected.
Schematic diagram: (a) diamond anvil device generating high pressure; (b) Spectral characteristics of thermal conductivity under high pressure; (c) Variation of thermal conductivity with pressure.
* Thanks to the team of paper authors for their strong support to this article.