Shi Zhenzhong, Baity P G, Sasagawa T, Popović Dragana
National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
Department of Physics, Florida State University, Tallahassee, FL 32306, USA.
Sci Adv. 2020 Feb 14;6(7):eaay8946. doi: 10.1126/sciadv.aay8946. eCollection 2020 Feb.
The phase diagram of underdoped cuprates in a magnetic field () is key to understanding the anomalous normal state of these high-temperature superconductors. However, the upper critical field ( ), the extent of superconducting (SC) phase with vortices, and the role of charge orders at high H remain controversial. Here we study stripe-ordered La-214, i.e., cuprates in which charge orders are most pronounced and zero-field SC transition temperatures are lowest. This enables us to explore the vortex phases in a previously inaccessible energy scale window. By combining linear and nonlinear transport techniques sensitive to vortex matter, we determine the - phase diagram, directly detect , and reveal novel properties of the high-field ground state. Our results demonstrate that quantum fluctuations and disorder play a key role as → , while the high-field ground state is likely a metal, not an insulator, due to the presence of stripes.
欠掺杂铜酸盐在磁场（）中的相图是理解这些高温超导体异常正常态的关键。然而，上临界场（）、具有涡旋的超导（SC）相的范围以及高磁场下电荷序的作用仍存在争议。在此，我们研究条纹有序的La - 214，即电荷序最为显著且零场超导转变温度最低的铜酸盐。这使我们能够在先前无法达到的能量尺度窗口中探索涡旋相。通过结合对涡旋物质敏感的线性和非线性输运技术，我们确定了 - 相图，直接检测到，并揭示了高场基态的新特性。我们的结果表明，当→时，量子涨落和无序起着关键作用，而由于条纹的存在，高场基态可能是金属，而非绝缘体。
