Development of membrane-based nanocalorimeter and its application to strongly correlated materials

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K21139
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 29:Applied condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Mizukami Yuta 東京大学, 大学院新領域創成科学研究科, 助教 (80734095)
• Project Period (FY): 2020-07-30 – 2022-03-31
• Keywords: メンブレン / カロリメータ / マイクロ単結晶 / ネマティック / トポロジー

Outline of Final Research Achievements

Using a high-resolution calorimeter, we have performed specific heat measurements on iron-based superconductors Fe(Se,S) and Fe(Se,Te), which have been difficult to measure specific heat due to their inhomogeneous chemical composition. Homogeneous micro single crystals were synthesized by chemical vapor transport method. Specific heat measurements on Fe(Se,Te) revealed that the electronic specific heat coefficient increases monotonically with increasing Te content, and that the low-energy excitations in the superconducting state evolve nonmonotonically. These features are expected to be related to the nematic and topological electronic states in this system.

Free Research Field

量子物性

Academic Significance and Societal Importance of the Research Achievements

本研究は、高感度熱量計の構築と、強相関電子系における新奇な電子状態の解明を目的としている。今回、比熱測定を行ったFe(Se,Te)においては、この系で発現する電子異方性(ネマティシティ)が、その超伝導状態と関係していることが示唆された。またこの系ではトポロジカルな性質も指摘されていることから、超伝導状態における新奇な素励起の可能性が期待される。