论文标题
空缺引起的吉泰旋转液体中状态的低能密度
Vacancy-induced low-energy density of states in the Kitaev spin liquid
论文作者
论文摘要
Kitaev Honeycomb模型由于具有分数化的Majorana激发及其在具有强旋转轨耦合的磁性莫特绝缘子中可能实现的物质化，因此引起了极大的关注。最近，5D电子化合物H $ _ {3} $ liir $ _ {2} $ o $ $ _ {6} $证明是Kitaev物理学的有力候选者，考虑到没有长距离有序磁状态的任何迹象。在这项工作中，我们证明了Kitaev模型中随机空缺的有限密度产生了惊人的低吸收性Majoragana Eigenmodes，并在H $ _ {3} $ _ {2} $ _ {2} $ o $ o $ o $ o $ $ o $ $ o $ o _} $ _ {6}的特定热量测量中重现了明显的动力法。从物理上讲，空缺可以源自各种来源，例如缺失的磁矩或存在非磁性杂质（真正的空位），也可以是由于强烈但罕见的键随机性（准胶质）而引起的磁矩局部弱耦合。我们从数字上表明，即使在低空位浓度下，空位效应也很容易检测到，并且对空位的性质也不对不同的通量背景敏感。我们还研究了位置稀释的Kitaev旋转液体对三旋链相互作用项的响应，该旋转术语破坏了时间反转对称性并模仿外部磁场。我们提出了一个场诱导的通量扇形跃迁，其中基态在较大场中变得无通量，从而明显地抑制了低温特异性热的热量。最后，我们讨论了在真实空缺的情况下悬挂悬挂的主要费用的效果，并表明它们通过Zeeman互动与所施加的磁场耦合也可以说明在H $ _ {3} $ _ {3} $ LIIR $ _ {2} $ o $ $ $ $ $ _ {6} $中观察到的高场限制中的缩放行为。
The Kitaev honeycomb model has attracted significant attention due to its exactly solvable spin-liquid ground state with fractionalized Majorana excitations and its possible materialization in magnetic Mott insulators with strong spin-orbit couplings. Recently, the 5d-electron compound H$_{3}$LiIr$_{2}$O$_{6}$ has shown to be a strong candidate for Kitaev physics considering the absence of any signs of a long-range ordered magnetic state. In this work, we demonstrate that a finite density of random vacancies in the Kitaev model gives rise to a striking pileup of low-energy Majorana eigenmodes and reproduces the apparent power-law upturn in the specific heat measurements of H$_{3}$LiIr$_{2}$O$_{6}$. Physically, the vacancies can originate from various sources such as missing magnetic moments or the presence of non-magnetic impurities (true vacancies), or from local weak couplings of magnetic moments due to strong but rare bond randomness (quasivacancies). We show numerically that the vacancy effect is readily detectable even at low vacancy concentrations and that it is not very sensitive neither to nature of vacancies nor to different flux backgrounds. We also study the response of the site-diluted Kitaev spin liquid to the three-spin interaction term, which breaks time-reversal symmetry and imitates an external magnetic field. We propose a field-induced flux-sector transition where the ground state becomes flux free for larger fields, resulting in a clear suppression of the low temperature specific heat. Finally, we discuss the effect of dangling Majorana fermions in the case of true vacancies and show that their coupling to an applied magnetic field via the Zeeman interaction can also account for the scaling behavior in the high-field limit observed in H$_{3}$LiIr$_{2}$O$_{6}$.
