Berry curvature memory through electrically driven stacking transitions
Berry curvature memory through electrically driven stacking transitions
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DOI：
10.1038/s41567-020-0947-0
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发表时间：
2020-06-29
期刊：
影响因子：
19.6
通讯作者：
Lindenberg, Aaron M.
中科院分区：
文献类型：
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作者：
Xiao, Jun;Wang, Ying;Lindenberg, Aaron M.
在二维层状量子材料中，层的堆叠顺序决定了晶体对称性以及诸如贝里曲率、拓扑和电子关联等电子性质（1 - 4）。电刺激能够影响准粒子相互作用和自由能态（5,6），使得动态改变堆叠顺序并揭示具有不同量子性质的隐藏结构成为可能。在此，我们展示了电驱动的堆叠转变，其可用于基于少层二碲化钨（WTe₂）中的贝里曲率设计非易失性存储器。面外电场和静电掺杂的相互作用控制面内层间滑动，并产生多种极性和中心对称的堆叠顺序。原位非线性霍尔输运表明，这种堆叠重排导致动量空间中具有层奇偶性选择性的贝里曲率记忆，其中贝里曲率及其偶极的符号反转仅发生在奇数层晶体中。我们的研究结果为探索隐藏堆叠顺序中拓扑、电子关联和铁电性之间的耦合开辟了一条途径，并在原子级薄的极限下展示了一种新的低能耗、电控拓扑存储器。提出了一种利用少层二碲化钨（WTe₂）堆叠顺序的动态改变来编码信息的存储器件。堆叠的改变同时改变了贝里曲率和霍尔输运，使得两种状态能够被区分。
In two-dimensional layered quantum materials, the stacking order of the layers determines both the crystalline symmetry and electronic properties such as the Berry curvature, topology and electron correlation(1-4). Electrical stimuli can influence quasiparticle interactions and the free-energy landscape(5,6), making it possible to dynamically modify the stacking order and reveal hidden structures that host different quantum properties. Here, we demonstrate electrically driven stacking transitions that can be applied to design non-volatile memory based on Berry curvature in few-layer WTe2. The interplay of out-of-plane electric fields and electrostatic doping controls in-plane interlayer sliding and creates multiple polar and centrosymmetric stacking orders. In situ nonlinear Hall transport reveals that such stacking rearrangements result in a layer-parity-selective Berry curvature memory in momentum space, where the sign reversal of the Berry curvature and its dipole only occurs in odd-layer crystals. Our findings open an avenue towards exploring coupling between topology, electron correlations and ferroelectricity in hidden stacking orders and demonstrate a new low-energy-cost, electrically controlled topological memory in the atomically thin limit.A memory device is proposed that uses a dynamical modification of the stacking order of few-layer WTe(2)to encode information. The change in stacking modifies both the Berry curvature and the Hall transport, allowing two states to be distinguished.