The interplay of quantum spin liquids with itinerant conduction electrons is of crucial interest for understanding layered structures composed of frustrated magnet and metal monolayers. Using parton-mean-field theory, we demonstrate here that a type-II heavy Fermi liquid, which is characterized by a vortex lattice in the slave boson condensate, can occur in the vicinity of the quantum phase transition separating fractionalized and heavy Fermi liquid phases. The magnetic flux threading each such vortex is about $v_f/137c$ times smaller than the magnetic flux threading vortices in type-II superconductors, where $v_f$ is the speed of magnetic excitations and $c$ the speed of light. This makes a magnetic observation of this effect challenging. We propose scanning tunneling spectroscopy instead and investigate its signatures. If a type-II heavy Fermi liquid is cooled into a type-II superconductor, vortices in the slave boson condensate and in the superconducting condensate mutually attract. We argue that the type-II heavy Fermi liquid thereby provides a compelling explanation for the magnetic memory observed recently [Persky et al., Nature (London) 607, 692 (2022)] in thermal cycles of $4\mathit{Hb}-{\mathrm{TaS}}_2$.

中文翻译：

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II型重费米液体和4Hb−TaS2的磁记忆

量子自旋液体与流动传导电子的相互作用对于理解由受挫磁体和金属单层组成的层状结构至关重要。使用部分子平均场理论，我们在这里证明了 II 型重费米液体（其特征是从属玻色子凝聚态中存在涡晶格）可以发生在分离分馏费米液相和重费米液相的量子相变附近。穿过每个这样的涡流的磁通量约为$v_F/137C$比 II 型超导体中的磁通穿过涡流小一倍，其中$v_F$是磁激励的速度，$C$光的速度。这使得磁力观察这种效应具有挑战性。我们建议改为扫描隧道光谱并研究其特征。如果将II型重费米液体冷却成II型超导体，则从属玻色子凝聚体和超导凝聚体中的涡旋会相互吸引。我们认为 II 型重费米液体因此为最近观察到的磁记忆提供了令人信服的解释 [Persky等人。，Nature (London) 607 , 692 (2022)]在热循环中$4\mathit{血红蛋白}-{\mathrm{硫化钽}}_2$。