Qi QIAN

Developing novel heterojunctions is a key challenge in advancing today's quantum information technology. Qi Qian is committed to constructing novel heterojunctions and superlattices and investigating their key quantum mechanisms, which provide critical references for the development of new quantum materials and devices.

She created an artificial van der Waals (vdW) superlattice through a spontaneous chemical intercalation of organic chiral molecules into inorganic layered 2D material, and invented a new type hybrid quantum material system-chiral molecule intercalation superlattice (CMIS).

The CMIS shows highly ordered crystal structure and mimics multi-tunneling junctions in series, which can enhance the spin-filtering effect to boost the spin polarization ratio.

Qi fabricated a spin tunneling junction using CMIS and demonstrated a record high spin polarization ratio of 60%, greatly surpassing the previously reported molecular systems by 2-3 orders.

Chiral induced spin selectivity effect in chiral molecules opens up possibilities to magnetic-field-free spin manipulation, which offers transformative applications in spintronics and quantum information technologies.

In another example, the chiral molecule intercalated 2D superconductors superlattice revealed a peculiar zero-field superconducting diode effect. This demonstrates the intriguing coupling between the molecular chirality and the solid-state superconductivity, which significantly modifies the property of the pristine superconductor and constitute critical signatures for the elusive chiral superconductivity.

This work shows the unprecedented opportunity to construct unconventional superconductivity by heterostructure engineering and the capability of marrying a diverse set of 2D materials with widely variable molecules by design.

Qi is also actively involved in the studies of many different quantum phenomenon in various vdW heterojunctions and superlattices, by creating systems with more diverse functions, including aggregation-induced emission, multiferroic effect, high temperature superconductivity, etc.