摘要
本研究采用变分蒙特卡罗方法，对包含一个巡游轨道（轨道0）和一个准局域轨道（轨道1）的双带t-J模型中的超导电性进行了探索。核心发现是，系统呈现出稳健的轨道选择性d波超导态，该超导态完全起源于巡游的轨道0。通过对超交换能级层次的分析表明，准局域化的轨道1通过倾向于形成局域轨道间束缚态来与超导电性竞争，这些束缚态作为能量缺陷破坏了相位相干性。相应地，超导序参量随轨道1占据数的增加而单调下降。受镍酸盐La3Ni2O7中超导电性的启发，这些结果强调了超越单带t-J框架的多轨道物理的关键作用，并为提高超导转变温度指明了具体途径：抑制源于局域dz2轨道的参与。
材料
方法
- variational Monte Carlo (VMC)
- two-band t-J model
关键词
- orbital selective d wave superconductivity
- superexchange energy hierarchy
- inter orbital bound states
亮点
- The superconducting order parameter decreases monotonically with increasing occupation of the localized orbital.
- Suppressing the involvement of the localized d_z2 orbital is identified as a route to enhance T_c.
结论
- A robust orbital-selective d-wave superconducting state emerges exclusively from the itinerant orbital.
- The quasi-localized orbital competes with superconductivity by favoring local inter-orbital bound states that disrupt phase coherence.
主要论断
- In the two-band t-J model, robust orbital-selective d-wave superconductivity arises exclusively from the itinerant orbital-0, while the quasi-localized orbital-1 suppresses it
- 证据: VMC calculations show that intra-orbital pair correlation in orbital-0 dominates, and the order parameter decreases monotonically with increasing occupancy of orbital-1
研究流程
- Model construction — d-wave superconductivity emerges exclusively from itinerant orbital
- 材料: Two-band t-J model on square lattice
- 方法: Variational Monte Carlo (VMC) with Gutzwiller projected wavefunctions
- 观察: Equal-time pair-pair correlations
- Analysis — Orbital-1 acts as competitor, suppressing SC
- 方法: Computation of superconducting order parameter; Orbital occupancy analysis
- 观察: Order parameter suppressed by increasing inter-orbital hopping or energy splitting