2025-02-10 ヒューストン大学
Magnetization Property Measurement System (MPMS) used in ultra-sensitive magnetization measurements.
＜関連情報＞
- https://uh.edu/news-events/stories/2025/february/02102025-tcsuh-breakthrough
- https://www.pnas.org/doi/abs/10.1073/pnas.2423102122
Bi0.5Sb1.5Te3における圧力誘起超伝導の生成、安定化、常圧での研究 Creation, stabilization, and investigation at ambient pressure of pressure-induced superconductivity in Bi0.5Sb1.5Te3
Liangzi Deng, Busheng Wang, Clayton Halbert, +12, and Ching-Wu Chu
Proceedings of the National Academy of Sciences Published:February 4, 2025
DOI:https://doi.org/10.1073/pnas.2423102122
Significance
As noted by the renowned material scientist Pol Duwez, almost all solids important to industry are in their metastable states. For example, since 1993, all record high superconducting transition temperatures have been achieved in materials under pressure, and thus in metastable states. Such extreme conditions present significant obstacles to exploring these metastable phases comprehensively and realizing the full promise of superconductivity. A solution is to stabilize them at ambient pressure. Here we used a pressure-quench protocol we recently developed to successfully stabilize the pressure-induced superconducting states in Bi0.5Sb1.5Te3 at ambient pressure and up to room temperature. This achievement marks a significant step toward maintaining at ambient pressure metastable states with desirable properties generated under extreme conditions for science and technology.
Abstract
In light of breakthroughs in superconductivity under high pressure, and considering that record critical temperatures (Tcs) across various systems have been achieved under high pressure, the primary challenge for higher Tc should no longer solely be to increase Tc under extreme conditions but also to reduce, or ideally eliminate, the need for applied pressure in retaining pressure-induced or -enhanced superconductivity. The topological semiconductor Bi0.5Sb1.5Te3 (BST) was chosen to demonstrate our approach to addressing this challenge and exploring its intriguing physics. Under pressures up to ~50 GPa, three superconducting phases (BST-I, -II, and -III) were observed. A superconducting phase in BST-I appears at ~4 GPa, without a structural transition, suggesting the possible topological nature of this phase. Using the pressure-quench protocol (PQP) recently developed by us, we successfully retained this pressure-induced phase at ambient pressure and revealed the bulk nature of the state. Significantly, this demonstrates recovery of a pressure-quenched sample from a diamond anvil cell at room temperature with the pressure-induced phase retained at ambient pressure. Other superconducting phases were retained in BST-II and -III at ambient pressure and subjected to thermal and temporal stability testing. Superconductivity was also found in BST with Tc up to 10.2 K, the record for this compound series. While PQP maintains superconducting phases in BST at ambient pressure, both depressurization and PQP enhance its Tc, possibly due to microstructures formed during these processes, offering an added avenue to raise Tc. These findings are supported by our density-functional theory calculations.
