研究目的
To study the thermopower in a two-dimensional semimetal existing in HgTe quantum wells 18–21 nm thick, both experimentally and theoretically, and to understand the roles of diffusion and phonon-drag components in the thermopower.
研究成果
The study provides the first experimental and theoretical analysis of the thermopower in a two-dimensional semimetal in HgTe quantum wells, highlighting the significant role of electron–hole scattering in both diffusion and phonon-drag components of the thermopower. The discrepancy between theory and experiment underscores the importance of further theoretical development to include phonon drag effects.
研究不足
The theory developed for the diffusion component of the thermopower underestimates the experimentally observed Seebeck coefficients, indicating the necessity to include the phonon drag contribution, which was not fully accounted for in the theoretical model.
1：Experimental Design and Method Selection:
The study involved measuring the thermopower in HgTe quantum wells under a temperature gradient created by a heater. The thermopower signal was measured at the double frequency using potentiometric contacts.
2：Sample Selection and Data Sources:
Rectangular samples based on wide HgTe quantum wells 20 nm thick with the (013) orientation were used. The thermopower was measured across these samples under varying temperatures and gate voltages.
3：List of Experimental Equipment and Materials:
A heater in the form of a thin metallic strip, a copper thermal anchor, calibrated thermistors, and a massive copper holder were used. The samples were about ten in number, with specific dimensions and segments.
4：Experimental Procedures and Operational Workflow:
An alternating current was passed through the metallic strip to create a temperature gradient. The temperature difference was controlled and measured using thermistors. The thermopower signal was then measured under these conditions.
5：Data Analysis Methods:
The experimental data were compared with theoretical predictions based on the diffusion contribution to the thermopower, considering electron–hole scattering.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
