Two distinct superconducting regimes in Ti4Co2O under pressures

Fuente: arXiv
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Auteurs principaux: Shi, Lifen, Ma, Keyuan, Ruan, Binbin, Wang, Zhen, Yang, Pengtao, Ren, Zhian, Sun, Jianping, Li, Gang, von Rohr, Fabian O., Wang, Bosen, Cheng, Jinguang
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Publié: 2026
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author Shi, Lifen
Ma, Keyuan
Ruan, Binbin
Wang, Zhen
Yang, Pengtao
Ren, Zhian
Sun, Jianping
Li, Gang
von Rohr, Fabian O.
Wang, Bosen
Cheng, Jinguang
author_facet Shi, Lifen
Ma, Keyuan
Ruan, Binbin
Wang, Zhen
Yang, Pengtao
Ren, Zhian
Sun, Jianping
Li, Gang
von Rohr, Fabian O.
Wang, Bosen
Cheng, Jinguang
contents We report on the pressure dependence of superconducting transition temperature Tc and upper critical field Bc2(0) through electrical transport of the Ti4Co2O superconductor (eg.,the superconducting transition temperature Tc = 2.5 K and the Bc2(0)=7.2T=2.9Tc). We find that the Tc exhibits non-monotonic pressure dependence:it rises monotonically at first with a pressure coefficient of dTc/dP=0.034 K/GPa, but rapidly decreases around 10-20 GPa, and then increases with the dTc/dP = 0.023 K/GPa, up to= 4.31 K at 69.7 GPa. Concurrently, the Bc2(0)exhibits a dome shaped pressure dependence, with its maximum at 5 GPa of almost twice the value at ambient pressure, exceeding the weak-coupling Pauli paramagnetic limit Bp throughout the whole pressure range. By comparing the normal-state and superconducting properties, we identify two distinct superconducting regimes, with a low-pressure superconducting phase characterized by an enhanced Bc2(0)values and Fermi-liquid normal-state electrical transport (the exponent n = 2), and a high-pressure superconducting phase with a monotonically increased Tc and an enhancement in phonon scatterings (the exponent n = 4). Room-temperature synchrotron X-ray diffraction indicates that there is no structural transition up to 55.8 GPa, which gives a relatively large bulk modulus of 192 GPa in comparison with other alloy superconductors. First-principles calculations suggest that the nonmonotonic Tc maybe closely related to the evolution of the density of states of Ti4Co2O upon compression, which is different from those of isostructural superconductors Ti4Ir2O and Nb4Rh2C. Our results show that even in the Ti4Co2O with weak spin-orbit coupling, superconductivity remains highly sensitive to the external stimuli such as pressure.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01893
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Two distinct superconducting regimes in Ti4Co2O under pressures
Shi, Lifen
Ma, Keyuan
Ruan, Binbin
Wang, Zhen
Yang, Pengtao
Ren, Zhian
Sun, Jianping
Li, Gang
von Rohr, Fabian O.
Wang, Bosen
Cheng, Jinguang
Superconductivity
Materials Science
We report on the pressure dependence of superconducting transition temperature Tc and upper critical field Bc2(0) through electrical transport of the Ti4Co2O superconductor (eg.,the superconducting transition temperature Tc = 2.5 K and the Bc2(0)=7.2T=2.9Tc). We find that the Tc exhibits non-monotonic pressure dependence:it rises monotonically at first with a pressure coefficient of dTc/dP=0.034 K/GPa, but rapidly decreases around 10-20 GPa, and then increases with the dTc/dP = 0.023 K/GPa, up to= 4.31 K at 69.7 GPa. Concurrently, the Bc2(0)exhibits a dome shaped pressure dependence, with its maximum at 5 GPa of almost twice the value at ambient pressure, exceeding the weak-coupling Pauli paramagnetic limit Bp throughout the whole pressure range. By comparing the normal-state and superconducting properties, we identify two distinct superconducting regimes, with a low-pressure superconducting phase characterized by an enhanced Bc2(0)values and Fermi-liquid normal-state electrical transport (the exponent n = 2), and a high-pressure superconducting phase with a monotonically increased Tc and an enhancement in phonon scatterings (the exponent n = 4). Room-temperature synchrotron X-ray diffraction indicates that there is no structural transition up to 55.8 GPa, which gives a relatively large bulk modulus of 192 GPa in comparison with other alloy superconductors. First-principles calculations suggest that the nonmonotonic Tc maybe closely related to the evolution of the density of states of Ti4Co2O upon compression, which is different from those of isostructural superconductors Ti4Ir2O and Nb4Rh2C. Our results show that even in the Ti4Co2O with weak spin-orbit coupling, superconductivity remains highly sensitive to the external stimuli such as pressure.
title Two distinct superconducting regimes in Ti4Co2O under pressures
topic Superconductivity
Materials Science
url https://arxiv.org/abs/2605.01893