科学家突破超导体临界电流极限

马克斯·普朗克物质结构动力学研究所的科学家利用超短电流脉冲，将超导体推向库珀对断裂的极限，超越了传统直流测量能够达到的临界电流水平1。研究团队采用300飞秒绿色激光脉冲（波长515纳米）激发光导开关，产生仅持续数皮秒的电流脉冲1。涡旋运动速度达到每秒数十公里，但在一皮秒的短时间内仅移动数十纳米1。

研究人员对NbN和YBCO两种超导材料进行了测试，发现了它们的显著差异1。NbN在远高于常规直流临界电流的阈值处突然失去超导性，而YBCO的超导性则随着电流增加而逐步减弱1。这些结果揭示了超导体微观结构与其量子行为之间的内在联系1。相关研究成果已发表于《自然物理学》2026年版，论文DOI为10.1038/s41567-026-03469-z1。

Researchers at the Max Planck Institute for the Structure and Dynamics of Matter have demonstrated a method to drive superconductors beyond the critical current thresholds normally measured through conventional direct current testing.1 Led by Andrea Cavalleri's research group, the team employed ultrashort electrical pulses to explore how superconducting materials respond at extreme current densities.1 The study tested two distinct superconducting materials—NbN and YBCO—and revealed fundamental differences in how these materials behave when subjected to such intense currents.1

The experimental technique relied on 300-femtosecond green laser pulses at a wavelength of 515 nanometers to excite an optically triggered switch, generating electrical pulses lasting only a few picoseconds.1 Despite vortex motion occurring at velocities of tens of kilometers per second, the movement within a single picosecond spans only tens of nanometers, allowing researchers to probe superconductivity under unprecedented conditions.1 The two materials exhibited markedly different responses: NbN displayed an abrupt loss of superconductivity at a threshold far exceeding its standard direct current critical current, while YBCO showed a gradual weakening of its superconducting properties as current increased.1 These findings illuminate the relationship between the microscopic structure of superconductors and their quantum behavior.1 The research was published in Nature Physics in 2026, with DOI 10.1038/s41567-026-03469-z.1