Researchers from the Beijing Academy of Quantum Information Sciences and Tsinghua University have made significant strides in understanding the behavior of superconductors, particularly in the context of nickelate materials. Their work, published in the journal Nature Communications, explores the phases that occur during the transition between superconducting and insulating states in these materials.
The team, led by Qi-Kun Xue and Danfeng Li, focused on infinite-layer nickelate superconducting films. They manipulated these films using spatially periodic network patterns to control the phase coherence of Cooper pairs, which are the electron pairs responsible for superconductivity. By doing so, they observed various bosonic phases, which are phases of matter characterized by the collective behavior of particles like Cooper pairs.
One of the key findings was the observation of magnetoresistance oscillations with a periodicity of h/2e, where h is Planck’s constant and e is the elementary charge. This periodicity provides direct evidence of 2e Cooper pairing in nickelates, confirming that these materials exhibit superconductivity through the pairing of two electrons.
The researchers also noted that the phase transitions were primarily driven by enhanced superconducting fluctuations. This means that the transitions between superconducting and insulating states are influenced by the dynamic behavior of Cooper pairs, which remain involved in charge transport even during the transitions.
Perhaps most intriguingly, the team observed two types of anomalous metallic phases. One emerged in finite magnetic fields, while the other persisted even in zero magnetic fields. These phases could be characterized by bosonic excitations, suggesting that vortices—tiny, whirlpool-like disturbances in the superconducting state—play a significant role in the ground states of these materials.
The practical implications for the energy sector are substantial. Understanding and controlling these phases could lead to the development of more robust and efficient superconducting materials. Superconductors have the potential to revolutionize the energy industry by enabling lossless power transmission, highly efficient power generation, and advanced energy storage solutions. By establishing nickelates as a key platform for investigating these phenomena, the researchers have opened new avenues for exploration and potential technological breakthroughs.
This article is based on research available at arXiv.