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arXiv 2406.12971cond-mat.str-el
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TMD莫尔系统中的超导体-绝缘体转变与解禁闭量子临界点

Superconductor-Insulator Transition in the TMD moiré systems and the Deconfined Quantum Critical Point

Nayan Myerson-Jain, Cenke Xu

AI总结:

本研究提出转角双层TMD莫尔系统中$\nu=1$处的超导体-绝缘体转变可用解禁闭量子临界点描述,分析了其对称性对应关系及应变下的相变类型,为该体系量子相变研究提供新理论视角。

摘要:

我们提出,近期在空穴填充因子$\nu=1$的转角双层过渡金属二硫化物(TMD)莫尔系统中观测到的超导体-绝缘体转变(SIT),或许可用解禁闭量子临界点(DQCP)来描述——该理论最初是为解释方格上奈尔序与价键固体(VBS)序之间的转变而提出的。原始DQCP涉及的关键对称性包括$\mathrm{SO}(3)_s$自旋对称性,以及VBS序的$C_4$晶格旋转对称性,该对称性在DQCP附近会扩大为$\mathrm{U}(1)_v$对称性。在当前研究的SIT中,$\mathrm{SO}(3)_s$自旋对称性的对应物是一种近似$\mathrm{SO}(3)_v$对称性,它支配三角晶格上不同晶序之间的转变;而$\mathrm{U}(1)_v$对称性的角色则由普通的电荷-$\mathrm{U}(1)_e$对称性取代。在DQCP处,$\mathrm{SO}(3)_v \times \mathrm{U}(1)_e$可能会扩大为一种涌现的$\mathrm{SO}(5)$对称性。在应变作用下,SIT会转变为显著的一级相变,或是一种“易面”DQCP,预计后者具有涌现的$\mathrm{O}(4)$对称性。

英文摘要:

We propose that the recently observed superconductor-insulator transition (SIT) in the twisted bilayer transition metal dichalcogenides moiré system at hole filling $ν= 1$ may be described by the deconfined quantum critical point (DQCP), which was originally proposed for the transition between the Néel order and the valence bond solid (VBS) order on the square lattice. The key symmetries involved in the original DQCP include a $\mathrm{SO}(3)_s$ spin symmetry, as well as a $C_4$ lattice rotation symmetry for the VBS order that is enlarged into a $\mathrm{U}(1)_v$ symmetry near the DQCP. In the current SIT under consideration, the counterpart of the $\mathrm{SO}(3)_s$ spin symmetry is an approximate $\mathrm{SO}(3)_v$ symmetry that transforms between different crystalline orders on the triangular lattice; and the role of the $\mathrm{U}(1)_v$ symmetry is replaced by the ordinary charge-$\mathrm{U}(1)_e$ symmetry. And at the DQCP the $\mathrm{SO}(3)_v \times \mathrm{U}(1)_e$ may enlarge into an emergent $\mathrm{SO}(5)$ symmetry. Under strain, the SIT is driven into either a prominent first order transition, or an "easy-plane" DQCP, which is expected to have an emergent $\mathrm{O}(4)$ symmetry.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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