More Like this

1. Interface-induced superconductivity in magnetic topological insulators

   https://doi.org/10.1126/science.adk1270  

   Yi, Hemian; Zhao, Yi-Fan; Chan, Ying-Ting; Cai, Jiaqi; Mei, Ruobing; Wu, Xianxin; Yan, Zi-Jie; Zhou, Ling-Jie; Zhang, Ruoxi; Wang, Zihao; et al (February 2024, Science)

   The interface between two different materials can show unexpected quantum phenomena. In this study, we used molecular beam epitaxy to synthesize heterostructures formed by stacking together two magnetic materials, a ferromagnetic topological insulator (TI) and an antiferromagnetic iron chalcogenide (FeTe). We observed emergent interface-induced superconductivity in these heterostructures and demonstrated the co-occurrence of superconductivity, ferromagnetism, and topological band structure in the magnetic TI layer—the three essential ingredients of chiral topological superconductivity (TSC). The unusual coexistence of ferromagnetism and superconductivity is accompanied by a high upper critical magnetic field that exceeds the Pauli paramagnetic limit for conventional superconductors at low temperatures. These magnetic TI/FeTe heterostructures with robust superconductivity and atomically sharp interfaces provide an ideal wafer-scale platform for the exploration of chiral TSC and Majorana physics. 

   more » « less
2. Meissner Effect and Nonreciprocal Charge Transport in Non‐Topological 1T‐CrTe ₂ /FeTe Heterostructures

   https://doi.org/10.1002/adma.202520598  

   Yan, Zi‐Jie; Chan, Ying‐Ting; Yuan, Wei; Wang, Annie G; Yi, Hemian; Wang, Zihao; Zhou, Lingjie; Rong, Hongtao; Zhuo, Deyi; Wang, Ke; et al (March 2026, Advanced Materials)

   ABSTRACT Interface‐induced superconductivity has recently been achieved by stacking a magnetic topological insulator layer on an antiferromagnetic FeTe layer. However, the mechanism driving this emergent superconductivity remains unclear. Here, we employ molecular beam epitaxy to grow a 1T‐CrTe₂layer, a 2D ferromagnet with a Curie temperature up to room temperature, on a FeTe layer. These 1T‐CrTe₂/FeTe heterostructures show superconductivity with a critical temperature of ∼12 K. Through magnetic force microscopy measurements, we observe the Meissner effect on the surface of the 1T‐CrTe₂layer. Our electrical transport measurements reveal that the 1T‐CrTe₂/FeTe heterostructures exhibit nonreciprocal charge transport behavior, characterized by a large magneto‐chiral anisotropy coefficient. The enhanced nonreciprocal charge transport in 1T‐CrTe₂/FeTe heterostructures provides a promising platform for exploring the magnetically controllable superconducting diode effect. 

   more » « less
3. A topological superconductor tuned by electronic correlations

   https://doi.org/10.1038/s41467-025-67957-1  

   Lin, Haoran; Jacobs, Christopher L; Yan, Chenhui; Nolan, Gillian M; Berruto, Gabriele; Singleton, Patrick; Nguyen, Khanh Duy; Bai, Yunhe; Gao, Qiang; Wu, Xianxin; et al (December 2025, Nature Communications)

   A topological superconductor, characterized by either a chiral order parameter or a topological surface state in proximity to bulk superconductivity, is foundational to topological quantum computing. A key open challenge is whether electron-electron interactions can tune such topological superconducting phase. Here, we provide experimental signatures of a unique topological superconducting phase in competition with electronic correlations in 10-unit-cell thick FeTexSe1-x films grown on SrTiO3 substrates. When the Te content x exceeds 0.7, we observe a topological transition marked by the emergence of a superconducting surface state. Near the FeTe limit, the system undergoes another transition where the surface state disappears, and superconductivity is suppressed. Theory suggests that electron-electron interactions in the odd-parity xy- band drives this second topological transition. The flattening and eventual decoherence of dxy-derived bands track the superconducting dome, linking correlation effects directly to superconducting coherent transport. Our work establishes many-body electronic correlations as a sensitive knob for tuning topology and superconductivity, offering a pathway to engineer new topological phases in correlated materials. 

   more » « less
4. Topological superconductor candidates PdBi2Te4 and PdBi2Te5 from a generic ab initio strategy

   https://doi.org/10.1038/s41524-023-01144-y  

   Luo, Aiyun; Li, Ying; Qin, Yi; Hu, Jingnan; Wang, Xiaoxu; Zou, Jinyu; Lian, Biao; Xu, Gang (December 2023, npj Computational Materials)

   Abstract Superconducting topological metals (SCTMs) have recently emerged as a promising platform of topological superconductivity (TSC) and Majorana zero modes for quantum computation. Despite their importance in both fundamental research and applications, SCTMs are very rare in nature. Here, we propose a strategy to design SCTMs by intercalating the superconducting units into the topological insulators. A program that characterizes the superconducting BdG Chern number of 2D BdG Hamiltonian from ab initio calculations is also developed. Following this strategy, PdBi₂Te₅and PdBi₂Te₄are found to be experimentally synthesizable and ideal SCTMs. Chiral TSC could be realized in such SCTMs by incorporating topological surface states with Zeeman effect, which can be realized by an external magnetic field or in proximity to ferromagnetic insulator. Our strategy provides a new method for identifying the SCTMs and TSC candidates, and the program makes it possible to design and modulate the TSC candidates from ab initio calculations. 

   more » « less
5. Detecting topological superconductivity via Berry curvature effects in spectral functions

   https://doi.org/10.1103/PhysRevB.111.064508  

   Liao, Yunxiang; Hsu, Yi-Ting (February 2025, Physical Review B)

   Experimental efforts on topological superconductivity (TSC) have primarily focused on the detection of Majorana boundary modes, while the bulk properties of TSC, particularly in two dimensions, remain relatively underexplored. In this work, we theoretically propose a distinctive signature in the spectral function away from the boundaries, capable of detecting two-dimensional (2D) chiral 𝑝-wave TSC induced in a Rashba spin-orbit-coupled heterostructure. This signature can be probed experimentally through angle-resolved photoemission spectroscopy or momentum- and energy-resolved tunneling spectroscopy under a weak magnetic field 𝐵. We show that within the topological phase, the spectral intensity of the lowest superconducting band at small momenta 𝑘∼0 brightens (darkens) linearly with increasing 𝐵, whereas it darkens (brightens) in the trivial phase when the Rashba system is electron (hole) doped. This sharp contrast arises from the phase-space Berry curvature (BC) of Bogoliubov quasiparticles, a novel quantum geometric property that generalizes the conventional momentum-space BC. The effect of this phase-space BC can also be detected by the differential conductance away from the boundaries. Our falsifiable prediction provides an experimental avenue for detecting Rashba-induced chiral 𝑝-wave TSC without relying on Majorana mode detection, addressing a key challenge in the realization of 2D TSC. 

   more » « less