The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stab...The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12122405,12274169,and 11574109)the Fundamental Research Funds for the Central Universities。
文摘The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.
