半填充光学Su-Schrieffer-Heeger-Hubbard模型中的单轴应变
The half-filled optical Su-Schrieffer-Heeger-Hubbard model with uniaxial strain
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中文总结 AI 辅助
该研究通过各向异性跳跃模拟单轴应变，结合Hubbard U，绘制了半填充SSH-Hubbard模型的相图，确定了键序波形成的临界温度，并展示了方向依赖的能隙形成。
中文摘要 AI 辅助
应变通过改变键长、跳跃振幅和晶格对称性，为控制电子相提供了一条直接途径。这些方面使得电子-声子（e-ph）耦合系统成为研究应变诱导效应的自然场所。Su-Schrieffer-Heeger（SSH）哈密顿量描述了巡游电子与调节跳跃的晶格自由度之间的耦合，因此预计会受到应变场的强烈影响。在半填充和双粒子晶格上，SSH相互作用在低温下驱动主导的键序波（BOW）关联，其中具有高动能短键与具有低动能长键沿四种可能图案交替排列。我们通过各向异性跳跃来模拟单轴应变，这打破了$90^\circ$旋转对称性并将BOW相简并度减少到两种。我们还引入了在位Hubbard U，它促进反铁磁关联，这种关联也（弱）由SSH相互作用本身驱动。我们在e-ph和Hubbard耦合平面上绘制了半填充相图，并确定了BOW形成的临界温度。利用解析延拓，我们还评估了谱函数，并展示了BOW相中方向依赖的能隙形成。
英文摘要
Strain offers a direct route to control electronic phases by altering bond lengths, hopping amplitudes, and lattice symmetries. These aspects make electron-phonon (e-ph) coupled systems a natural setting to study strain-induced effects. The Su-Schrieffer-Heeger (SSH) Hamiltonian describes the coupling between itinerant electrons and lattice degrees of freedom that modulate hopping and is thus expected to be strongly affected by strain fields. At half-filling and on a bipartite lattice, the SSH interactions drive dominant bond-order-wave (BOW) correlations at low- temperature in which short bonds with high kinetic energy alternate with long bonds with low kinetic energy along four possible patterns. We model uniaxial strain through anisotropic hopping, which breaks the $90^\circ$ rotational symmetry and reduces the BOW phase degeneracy to two. We also include an on-site Hubbard U that promotes antiferromagnetic correlations that are also (weakly) driven by the SSH interaction itself. We map out the half-filled phase diagram in the plane of the e-ph and Hubbard couplings, and determine the critical temperature of BOW formation. Using analytic continuation, we also evaluate the spectral function and demonstrate directionally dependent gap formation in the BOW phase
发表机构
- University of California, Davis（加州大学戴维斯分校）
- The University of Tennessee（田纳西大学）
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