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arXiv 2509.03469cond-mat.str-elcond-mat.mes-hallcond-mat.mtrl-sci
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Bi$_4$I$_4$中位移型拓扑相变过程中涌现表面态的特征

Signatures of emergent surface states across a displacive topological phase transition in Bi$_4$I$_4$

Deep Singha Roy, Sk Kalimuddin, Subrata Pachhal, Saikat Mondal, Soham Das, Sukanya Jana, Arnab Bera, Satyabrata Bera, Tuhin Debnath, Ankan Bag, Souvik Pramanik,… 展开作者

Deep Singha Roy, Sk Kalimuddin, Subrata Pachhal, Saikat Mondal, Soham Das, Sukanya Jana, Arnab Bera, Satyabrata Bera, Tuhin Debnath, Ankan Bag, Souvik Pramanik, Sudipta Chatterjee, Sanjib Naskar, Shishir Kumar Pandey, Adhip Agarwala, Mintu Mondal

AI总结:

本研究通过实空间电流成像和电阻涨落谱,观测到Bi$_4$I$_4$中由一阶结构变化介导的位移型拓扑相变的实验特征,揭示了经典热力学相变与拓扑量子现象的复杂相互作用。

摘要:

涉及晶体对称性破缺的拓扑相变为探索对称性、拓扑结构与涌现量子现象之间的相互作用提供了沃土。近期发现的准一维拓扑材料Bi$_4$I$_4$,据预测在高温下具有拓扑非平庸的无隙表面态,且会在有限温度下发生相变,转变为低温有隙相。本文呈现了该室温相变的实验特征:该相变从具有表面态的高温β相转变为存在棱态的有隙α相。我们利用实空间电流成像和电阻涨落谱,识别出由一阶热力学结构变化介导的位移型拓扑相变的特征。在β相刚涌现的附近区域,我们观测到显著的电报噪声,表明存在带拓扑表面态的涨落相畴。空间分辨的电流图揭示了β相中电子通过无隙表面态输运,而在转变为具有局域传导通道(或棱模)的α相后,该输运模式消失。我们的实验结果得到了第一性原理估算和拓扑位移相变有效理论的支持,确立了Bi$_4$I$_4$作为展现经典热力学相变与拓扑量子现象复杂相互作用的候选材料。

英文摘要:

Topological phase transitions involving crystalline symmetry breaking provide a fertile ground to explore the interplay between symmetry, topology, and emergent quantum phenomena. Recently discovered quasi-one-dimensional topological material, Bi$_4$I$_4$, has been predicted to host topologically non-trivial gapless surfaces at high temperature, which undergo a finite temperature phase transition to a low temperature gapped phase. Here we present experimental signatures of this room temperature phase transition from a high-temperature $β$-phase with a surface state to a gapped $α$-phase hosting hinge states. Using real-space current mapping and resistance fluctuation spectroscopy, we identify signatures of a displacive topological phase transition mediated by a first-order thermodynamic structural change. Near the emergence of $β$-phase, we observe pronounced telegraphic noise, indicating fluctuating phase domains with topological surface states. The spatially resolved current map reveals electron transport via the gapless surface states in the $β$-phase, which vanishes upon transitioning to the $α$-phase with localized conduction channels (or hinge modes). Our experimental results, supported by first principles estimates and effective theory of a topological displacive phase transition, establish Bi$_4$I$_4$ as a candidate material showing intricate interplay of classical thermodynamic phase transitions with topological quantum phenomena.

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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