The recently discovered titanium-based kagome metal ATi_(3)Bi_(5)(A=Cs,Rb)provides a new platform to explore novel quantum phenomena.In this work,the transport properties of ATi_(3)Bi_(5)(A=Cs,Rb)are systematically in...The recently discovered titanium-based kagome metal ATi_(3)Bi_(5)(A=Cs,Rb)provides a new platform to explore novel quantum phenomena.In this work,the transport properties of ATi_(3)Bi_(5)(A=Cs,Rb)are systematically investigated under high pressure.Although ATi_(3)Bi_(5)(A=Cs,Rb)shows no evidence of superconductivity at ambient pressure,the pressure-induced double-dome superconductivity is observed in both compounds,resembling the superconducting phase diagram of AV_(3)Sb_(5)(A=Cs,Rb,and K)under pressure.High-pressure X-ray difraction measurements exclude the pressure-induced structural phase transition.A slope change in the c/a ratio was found between 12.4 and 14.9 GPa,indicating the occurrence of lattice distortion.The distinct changes in the electronic band structure revealed by frst-principles calculations further explain the emergence of superconductivity in the two domes.These fndings suggest that pressure can efectively tune the electronic properties of ATi_(3)Bi_(5),providing new insights into the rich physics of kagome metals.展开更多
The well-known physicist Chen Ning Yang[1]once summarized that the three main themes of 20th-century physics are quantization,the phase factor,and symmetry.Phase,as a fundamental characteristic of quantum mechanics,se...The well-known physicist Chen Ning Yang[1]once summarized that the three main themes of 20th-century physics are quantization,the phase factor,and symmetry.Phase,as a fundamental characteristic of quantum mechanics,serves as the cornerstone for all interference phenomena.In 1984,Berry pointed out that when the parameters in the Hamiltonian evolve slowly enough(adiabatically)to return to their original values,the wave function of a two-level system acquires a pure geometric phase factor,known as the Berry phase[2].This phase factor is precisely the holonomy in a Hermitian line bundle[3].In 1987,Aharonov and Anandan[4]further discovered that,in non-adiabatic conditions,there exists a geometric phase factor known as the A-A phase,arising in a process called cyclic evolution,which can be regarded as a non-adiabatic generalization of the Berry phase.展开更多
基金supported by the Natural Science Foundation of China(Grant No.12174064)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)+5 种基金the Innovation Program for Quantum Science and Technology(Grant No.2024ZD0300104)the support by the Natural Science Foundation of China(Grant No.12204383)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2023QNRC001)the Young Talent Fund of the Association for Science and Technology in Shaanxi(Grant No.CLGC202201)supported by the open project of Beijing National Laboratory for Condensed Matter Physics(Grant No.ZBJ2106110017)the Double First-Class Initiative Fund of Shanghai Tech University。
文摘The recently discovered titanium-based kagome metal ATi_(3)Bi_(5)(A=Cs,Rb)provides a new platform to explore novel quantum phenomena.In this work,the transport properties of ATi_(3)Bi_(5)(A=Cs,Rb)are systematically investigated under high pressure.Although ATi_(3)Bi_(5)(A=Cs,Rb)shows no evidence of superconductivity at ambient pressure,the pressure-induced double-dome superconductivity is observed in both compounds,resembling the superconducting phase diagram of AV_(3)Sb_(5)(A=Cs,Rb,and K)under pressure.High-pressure X-ray difraction measurements exclude the pressure-induced structural phase transition.A slope change in the c/a ratio was found between 12.4 and 14.9 GPa,indicating the occurrence of lattice distortion.The distinct changes in the electronic band structure revealed by frst-principles calculations further explain the emergence of superconductivity in the two domes.These fndings suggest that pressure can efectively tune the electronic properties of ATi_(3)Bi_(5),providing new insights into the rich physics of kagome metals.
基金the National Key Research and Development Program of China(2022YFA1405100)the National Natural Science Foundation of China(12241405,12174384,and 12404146)。
文摘The well-known physicist Chen Ning Yang[1]once summarized that the three main themes of 20th-century physics are quantization,the phase factor,and symmetry.Phase,as a fundamental characteristic of quantum mechanics,serves as the cornerstone for all interference phenomena.In 1984,Berry pointed out that when the parameters in the Hamiltonian evolve slowly enough(adiabatically)to return to their original values,the wave function of a two-level system acquires a pure geometric phase factor,known as the Berry phase[2].This phase factor is precisely the holonomy in a Hermitian line bundle[3].In 1987,Aharonov and Anandan[4]further discovered that,in non-adiabatic conditions,there exists a geometric phase factor known as the A-A phase,arising in a process called cyclic evolution,which can be regarded as a non-adiabatic generalization of the Berry phase.
