arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~

分数填充下扭曲双层MoTe₂相图的大规模理论研究:与现有实验的一致与矛盾

Large scale theoretical investigation of the phase diagram of twisted bilayer MoTe$_2$ at fractional fillings: agreements and contradictions with current experiments

Heqiu Li, Jiabin Yu, Xiaodong Xu, B. Andrei Bernevig, N. Regnault

arXiv 2608.23675首次发表:更新:

AI 中文总结

研究通过精确对角化对比两种带模型,揭示扭曲双层MoTe₂分数填充下的相图特征,明确多带效应对与实验定量比较的关键作用,未发现ν=-3/2处非阿贝尔Pfaffian态的证据。

AI 中文摘要

我们对扭曲双层MoTe₂中相互作用驱动的相进行了全面的精确对角化研究,研究涵盖了实验相关的扭曲角(2.13°–4°)和空穴填充情况。利用连续模型莫尔能带,我们比较了每谷单带(1BPV)投影与包含相互作用驱动能带混合的每谷双带(2BPV)计算,同时对广泛使用的一阶连续模型和无参数DFT“无拟合”模型进行了基准测试。在奇分母填充下,2BPV计算再现了θ≈3.7°附近分数陈绝缘体(FCI)的实验观测层级,包括ν=-2/3、-3/5和-4/7处的鲁棒不可压缩态,且正确发现ν=-3/7处不存在FCI,还更倾向于在ν=-1/3处形成电荷密度波基态而非FCI。在半填充ν=-1/2处,1BPV计算呈现出明显的复合费米液体(CFL)特征,而2BPV计算中的能带混合会破坏CFL基态。最后,受θ≈2.13°处朗道能级类比的启发,我们在完全极化的自旋区域测试了ν=-3/2处提出的非阿贝尔Pfaffian态,但在所研究的模型和参数范围内未发现该态的证据。我们的结果为扭曲双层MoTe₂中的关联拓扑相建立了统一的数值基准,并阐明了多带物理在与实验定量比较中至关重要的地方。

英文摘要

We present a comprehensive exact-diagonalization study of interaction-driven phases in twisted bilayer MoTe$_2$ across experimentally relevant twist angles ($2.13^\circ$--$4^\circ$) and hole fillings. Using continuum-model moiré bands, we compare the one-band-per-valley (1BPV) projection with a two-band-per-valley (2BPV) calculation that includes interaction-driven band mixing, and we benchmark both the widely used first-harmonic continuum model and a parameter-free DFT ``fitting-free'' model. At odd-denominator fillings, the 2BPV calculation reproduces the experimentally observed hierarchy of fractional Chern insulators (FCIs) around $θ\approx 3.7^\circ$, including robust incompressible states at $ν=-2/3$, $-3/5$, and $-4/7$ while correctly finding the absence of an FCI at $ν=-3/7$, and it favors a charge density wave ground state at $ν=-1/3$ over the FCI. At half filling $ν=-1/2$, the 1BPV calculation exhibits clear composite Fermi liquid (CFL) signatures, whereas the band mixing in 2BPV calculations destabilizes the CFL ground state. Finally, motivated by the Landau-level analogy at $θ\approx 2.13^\circ$, we test the proposed non-abelian Pfaffian state at $ν=-3/2$ in the fully-polarized spin sector but find no evidence for this state within the models and parameters studied. Our results establish a unified numerical benchmark for correlated and topological phases in twisted bilayer MoTe$_2$ and clarify where multi-band physics is essential for a quantitative comparison with experiments.

论文原文

arXiv 摘要页 · PDF 原文 · HTML 原文

↑