TY - JOUR
T1 - Higher superconducting transition temperature by breaking the universal pressure relation
AU - Deng, Liangzi
AU - Zheng, Yongping
AU - Wu, Zheng
AU - Huyan, Shuyuan
AU - Wu, Hung Cheng
AU - Nie, Yifan
AU - Cho, Kyeongjae
AU - Chu, Ching Wu
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank M. Eremets for advice in developing the mini-DAC and J. B. Zhang, X. J. Chen, R. Dumas, and S. Li for helpful discussions. The work performed at the Texas Center for Superconductivity at the University of Houston is supported by US Air Force Office of Scientific Research Grant FA9550-15-1-0236, the T. L. L. Temple Foundation, the John J. and Rebecca Moores Endowment, and the State of Texas through the Texas Center for Superconductivity at the University of Houston. The work performed at the Department of Materials Science & Engineering at the University of Texas at Dallas is funded in part by International Energy Joint R & D Program 20168510011350 of Korea Institute of Energy Technology Evaluation and Planning Grant funded by the Ministry of Knowledge Economy, Korean Government.
Publisher Copyright:
© 2019 National Academy of Sciences. All Rights Reserved.
PY - 2019/2/5
Y1 - 2019/2/5
N2 - By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconducting transition temperatures (T c s) of the mono-layer Bi 2 Sr 2 CuO 6 + δ (Bi2201) and bilayer Bi 2 Sr 2 CaCu 2 O 8 + δ (Bi2212) to beyond the maximum T c s (T c-max s) predicted by the universal relation between T c and doping (p) or pressure (P) at higher pressures. The T c of underdoped Bi2201 initially increases from 9.6 K at ambient to a peak at 23 K at 26 GPa and then drops as expected from the universal T c -P relation. However, at pressures above 40 GPa, T c rises rapidly without any sign of saturation up to 30 K at 51 GPa. Similarly, the T c for the slightly overdoped Bi2212 increases after passing a broad valley between 20 and 36 GPa and reaches 90 K without any sign of saturation at 56 GPa. We have, therefore, attributed this T c resurgence to a possible pressure-induced electronic transition in the cuprate compounds due to a charge transfer between the Cu 3d x 2 −y 2 and the O 2p bands projected from a hybrid bonding state, leading to an increase of the density of states at the Fermi level, in agreement with our density functional theory calculations. Similar T c -P behavior has also been reported in the trilayer Br 2 Sr 2 Ca 2 Cu 3 O 10 + δ (Bi2223). These observations suggest that higher T c s than those previously reported for the layered cuprate high-temperature superconductors can be achieved by breaking away from the universal T c -P relation through the application of higher pressures.
AB - By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconducting transition temperatures (T c s) of the mono-layer Bi 2 Sr 2 CuO 6 + δ (Bi2201) and bilayer Bi 2 Sr 2 CaCu 2 O 8 + δ (Bi2212) to beyond the maximum T c s (T c-max s) predicted by the universal relation between T c and doping (p) or pressure (P) at higher pressures. The T c of underdoped Bi2201 initially increases from 9.6 K at ambient to a peak at 23 K at 26 GPa and then drops as expected from the universal T c -P relation. However, at pressures above 40 GPa, T c rises rapidly without any sign of saturation up to 30 K at 51 GPa. Similarly, the T c for the slightly overdoped Bi2212 increases after passing a broad valley between 20 and 36 GPa and reaches 90 K without any sign of saturation at 56 GPa. We have, therefore, attributed this T c resurgence to a possible pressure-induced electronic transition in the cuprate compounds due to a charge transfer between the Cu 3d x 2 −y 2 and the O 2p bands projected from a hybrid bonding state, leading to an increase of the density of states at the Fermi level, in agreement with our density functional theory calculations. Similar T c -P behavior has also been reported in the trilayer Br 2 Sr 2 Ca 2 Cu 3 O 10 + δ (Bi2223). These observations suggest that higher T c s than those previously reported for the layered cuprate high-temperature superconductors can be achieved by breaking away from the universal T c -P relation through the application of higher pressures.
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U2 - 10.1073/pnas.1819512116
DO - 10.1073/pnas.1819512116
M3 - Article
C2 - 30679281
AN - SCOPUS:85061117687
VL - 116
SP - 2004
EP - 2008
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 6
ER -