Nature, 30 January 2025, Volume 637, Issue 8048《天然》2025年1月30日，第637卷，8048期?物理学PhysicsUltrabroadband integrated electro-optic frequency comb in lithium tantalate钽酸锂中超宽带集成电光频率梳▲ 作者：Junyin Zhang, Chengli Wang, Connor Denney, Johann Riemensberger, Grigory Lihachev, Jianqi Hu, Wil Kao, Terence Blésin, Nikolai Kuznetsov, Zihan Li, Mikhail Churaev, Xin Ou, Gabriel Santamaria-Botello Tobias J. Kippenberg▲ 链接：https://www.nature.com/articles/s41586-024-08354-4▲ 择要：基于Kerr参数振荡的集成频率梳产生器曾经发生了芯片级、千兆赫距离的梳，存在跨超年夜范围电信、低噪声微波分解、光探测跟测距以及天体物理光谱仪校准的新利用。铌酸锂（LiNbO3）光子集成电路（PICs）的最新停顿推进了芯片范围的电光（EO）频率梳，供给准确的梳线定位跟简略的操纵，而不依附于构成耗散克尔孤子。但是，因为驱动非谐振电容电极所需的微波功率年夜，以及LiNbO3的强固有双折射，现在集成EO梳子的光谱笼罩范畴无限。研讨者经由过程集成三重谐振构造战胜了这两个挑衅，将单片微波集成电路与基于近来呈现的薄膜LiTaO3的PICs相联合。与传统的非谐振微波计划比拟，经由过程共振加强的EO彼此感化跟增加的双折射，研讨实现了4倍的梳子跨度扩大跟16倍的功率下降。在混杂集成激光二极管的驱动下，梳子的跨度超越450纳米（超越60太赫兹），有2000多条线，而产生器的占空中积仅为1平方厘米。别的，研讨者还察看到强EO耦合招致梳子存在范畴增添，濒临光学微谐振器的全自在光谱范畴。超宽带梳状产生器与掉谐不断定操纵相联合，能够推动芯片级光谱剖析跟超低噪声毫米波分解，并解锁八度跨度的EO梳状器。微波跟光子协同计划的方式能够扩大到普遍的集成光电利用。▲ Abstract：The integrated frequency comb generator based on Kerr parametric oscillation1 has led to chip-scale, gigahertz-spaced combs with new applications spanning hyperscale telecommunications, low-noise microwave synthesis, light detection and ranging, and astrophysical spectrometer calibration. Recent progress in lithium niobate (LiNbO3) photonic integrated circuits (PICs) has resulted in chip-scale, electro-optic (EO) frequency combs, offering precise comb-line positioning and simple operation without relying on the formation of dissipative Kerr solitons. However, current integrated EO combs face limited spectral coverage due to the large microwave power required to drive the non-resonant capacitive electrodes and the strong intrinsic birefringence of LiNbO3. Here we overcome both challenges with an integrated triply resonant architecture, combining monolithic microwave integrated circuits with PICs based on the recently emerged thin-film lithium tantalate (LiTaO3). With resonantly enhanced EO interaction and reduced birefringence in LiTaO3, we achieve a fourfold comb span extension and a 16-fold power reduction compared to the conventional, non-resonant microwave design. Driven by a hybrid integrated laser diode, the comb spans over 450?nm (more than 60?THz) with more than 2,000 lines, and the generator fits within a compact 1-cm2 footprint. We additionally observe that the strong EO coupling leads to an increased comb existence range approaching the full free spectral range of the optical microresonator. The ultra-broadband comb generator, combined with detuning-agnostic operation, could advance chip-scale spectrometry and ultra-low-noise millimetre wave synthesis and unlock octave-spanning EO combs. The methodology of co-designing microwave and photonics can be extended to a wide range of integrated EOs applications.Moiré-driven topological electronic crystals in twisted graphene歪曲石墨烯中摩尔驱动的拓扑电子晶体▲ 作者：Ruiheng Su, Dacen Waters, Boran Zhou, Kenji Watanabe, Takashi Taniguchi, Ya-Hui Zhang, Matthew Yankowitz Joshua Folk▲ 链接：https://www.nature.com/articles/s41586-024-08239-6▲择要：在粘稠的二维电子气体中，库仑彼此感化能够稳固维格纳晶体的构成。固然维格纳晶体在拓扑上是眇乎小哉的，但据猜测，局部添补带中的电子能够自发地攻破持续的平移对称性跟时光反转对称性，从而发生一种被称为变态霍尔晶体的拓扑电子晶体。研讨者讲演了歪曲的双层—三层石墨烯中异样霍尔晶体的狭义版本的特点，其构成是由莫尔阱势驱动的。晶体构成于每4个摩尔粒子（ν=1/4）有1个电子的带添补，使单元细胞面积增添了4倍，与整数目子变态霍尔效应相分歧。态的陈数是特殊可调的，它能够在电场跟磁场的感化下在+1跟-1之间可逆地切换。其余多少个拓扑电子晶体呈现在适度的磁场中，来源于ν=1/3,1/2,2/3跟3/2。彼此感化润饰能带的量子多少何可能与原始母能带的量子多少何十分差别，这使得可能在将来发明相干驱动的拓扑景象。▲ Abstract：In a dilute two-dimensional electron gas, Coulomb interactions can stabilize the formation of a Wigner crystal. Although Wigner crystals are topologically trivial, it has been predicted that electrons in a partially filled band can break continuous translational symmetry and time-reversal symmetry spontaneously, resulting in a type of topological electron crystal known as an anomalous Hall crystal. Here we report signatures of a generalized version of the anomalous Hall crystal in twisted bilayer–trilayer graphene, whose formation is driven by the moiré potential. The crystal forms at a band filling of one electron per four moiré unit cells (ν?=?1/4) and quadruples the unit-cell area, coinciding with an integer quantum anomalous Hall effect. The Chern number of the state is exceptionally tunable, and it can be switched reversibly between +1 and ?1 by electric and magnetic fields. Several other topological electronic crystals arise in a modest magnetic field, originating from ν?=?1/3, 1/2, 2/3 and 3/2. The quantum geometry of the interaction-modified bands is likely to be very different from that of the original parent band, which enables possible future discoveries of correlation-driven topological phenomena.Synthesis of a semimetallic Weyl ferromagnet with point Fermi surface存在点费米名义的半金属Weyl铁磁体的分解▲ 作者：Ilya Belopolski, Ryota Watanabe, Yuki Sato, Ryutaro Yoshimi, Minoru Kawamura, Soma Nagahama, Yilin Zhao, Sen Shao, Yuanjun Jin, Yoshihiro Kato, Yoshihiro Okamura, Xiao-Xiao Zhang, Yukako Fujishiro, Youtarou Takahashi, Max Hirschberger, Atsushi Tsukazaki, Kei S. Takahashi, Ching-Kai Chiu, Guoqing Chang, Masashi Kawasaki, Naoto Nagaosa Yoshinori Tokura▲ 链接：https://www.nature.com/articles/s41586-024-08330-y▲ 择要：由新兴的拓扑费米子把持的量子资料曾经成为物理学的基石。石墨烯中的狄拉克费米子形成了摩尔量子物资的基本，磁拓扑绝缘体中的狄拉克费米子使得量子变态霍尔效应（QAH）的发明成为可能。比拟之下，很少有资料的电磁呼应是由出现的Weyl费米子主导的。多少乎全部已知的Weyl资料绝年夜少数都是金属，而且在很年夜水平上由有关的惯例电子把持。这项研讨从实践上猜测并在试验上察看了范德华（Cr,Bi）2Te3中的半金属Weyl铁磁体。在输运中，他们发明了一个年夜于0.5的记载体异样霍尔角以及非金属电导率，这是一个与传统铁磁体一模一样的轨制。联合对称性剖析，研讨数据标明一个由两个Weyl点构成的半金属费米名义，存在超越体布里渊区线性尺寸75%的宏大分别，而且不其余电子态。研讨者应用开始进的晶体分解技巧，普遍调剂电子构造，使其可能泯没Weyl状况，并可视化一个奇特的拓扑相图，表现普遍的陈氏绝缘，Weyl半金属跟磁性半导体地区。研讨者表现，对半金属Weyl铁磁体的察看为研讨新的相干态跟非线性景象以及零磁场Weyl自旋电子跟光学器件供给了一条道路。▲ Abstract：Quantum materials governed by emergent topological fermions have become a cornerstone of physics. Dirac fermions in graphene form the basis for moiré quantum matter and Dirac fermions in magnetic topological insulators enabled the discovery of the quantum anomalous Hall (QAH) effect. By contrast, there are few materials whose electromagnetic response is dominated by emergent Weyl fermions. Nearly all known Weyl materials are overwhelmingly metallic and are largely governed by irrelevant, conventional electrons. Here we theoretically predict and experimentally observe a semimetallic Weyl ferromagnet in van der Waals（Cr,Bi）2Te3. In transport, we find a record bulk anomalous Hall angle of greater than 0.5 along with non-metallic conductivity, a regime that is strongly distinct from conventional ferromagnets. Together with symmetry analysis, our data suggest a semimetallic Fermi surface composed of two Weyl points, with a giant separation of more than 75% of the linear dimension of the bulk Brillouin zone, and no other electronic states. Using state-of-the-art crystal-synthesis techniques, we widely tune the electronic structure, allowing us to annihilate the Weyl state and visualize a unique topological phase diagram exhibiting broad Chern insulating, Weyl semimetallic and magnetic semiconducting regions. Our observation of a semimetallic Weyl ferromagnet offers an avenue towards new correlated states and nonlinear phenomena, as well as zero-magnetic-field Weyl spintronic and optical devices.Enhanced energy storage in antiferroelectrics via antipolar frustration经由过程反极性波折加强反铁电体的能量存储▲ 作者：Bingbing Yang, Yiqian Liu, Ru-Jian Jiang, Shun Lan, Su-Zhen Liu, Zhifang Zhou, Lvye Dou, Min Zhang, Houbing Huang, Long-Qing Chen, Yin-Lian Zhu, Shujun Zhang, Xiu-Liang Ma, Ce-Wen Nan Yuan-Hua Lin▲ 链接：https://www.nature.com/articles/s41586-024-08505-7▲择要：介质储能电容器充放电速率快、牢靠性高，在尖端电子电气装备中施展侧重要感化。为了寻求电容器的小型化跟集成化，电介质必需供给高能量密度跟效力。存在反平行偶极子构造的反铁电体因为其在场致铁电态中可疏忽的残余极化跟高的最年夜极化而在高机能能量存储中存在主要的意思。但是，低反铁电—铁电相变场跟随同的年夜磁滞消耗会下降能量密度跟牢靠性。在相场模仿的领导下，研讨者提出了一种新的战略，经由过程参加非极性或极性身分来挫败反铁电体中的反极性有序。试验标明，该方式无效地调理了反铁电—铁电相变场，同时减小了磁滞消耗。在基于PbZrO3的薄膜中，他们在5.51 MV cm?1的电场下实现了189 J cm?3的反铁电体中创记录的高能量密度以及81%的高效力，可与开始进的储能介质相媲美。扫描透射电子显微镜的原子标准表征直接提醒了疏散的非极性区妨碍了近程反极性有序，有助于进步机能。这种战略为把持极化散布跟进步反铁电体的储能机能供给了新的机遇。▲ Abstract：Dielectric-based energy storage capacitors characterized with fast charging and discharging speed and reliability play a vital role in cutting-edge electrical and electronic equipment. In pursuit of capacitor miniaturization and integration, dielectrics must offer high energy density and efficiency. Antiferroelectrics with antiparallel dipole configurations have been of significant interest for high-performance energy storage due to their negligible remanent polarization and high maximum polarization in the field-induced ferroelectric state. However, the low antiferroelectric–ferroelectric phase-transition field and accompanying large hysteresis loss deteriorate energy density and reliability. Here, guided by phase-field simulations, we propose a new strategy to frustrate antipolar ordering in antiferroelectrics by incorporating non-polar or polar components. Our experiments demonstrate that this approach effectively tunes the antiferroelectric–ferroelectric phase-transition fields and simultaneously reduces hysteresis loss. In PbZrO3-based films, we hence realized a record high energy density among all antiferroelectrics of 189?J?cm?3 along with a high efficiency of 81% at an electric field of 5.51?MV?cm?1, which rivals the most state-of-the-art energy storage dielectrics. Atomic-scale characterization by scanning transmission electron microscopy directly revealed that the dispersed non-polar regions frustrate the long-range antipolar ordering, which contributes to the improved performance. This strategy presents new opportunities to manipulate polarization profiles and enhance energy storage performances in antiferroelectrics.化学ChemistryDurable all-inorganic perovskite tandem photovoltaics耐用的全无机钙钛矿串联光伏电池▲ 作者：Chenghao Duan, Kaicheng Zhang, Zijian Peng, Shiang Li, Feilin Zou, Feng Wang, Jiong Li, Zheng Zhang, Chang Chen, Qiliang Zhu, Jianhang Qiu, Xinhui Lu, Ning Li, Liming Ding, Christoph J. Brabec, Feng Gao Keyou Yan▲ 链接：https://www.nature.com/articles/s41586-024-08432-7▲ 择要：用无机阳离子（如Cs+）代替无机阳离子（如甲基铵跟甲脒）制备全无机钙钛矿是进步钙钛矿太阳能电池（PSCs）临时光稳固性跟热稳固性的无效观点。因而，无机钙钛矿串联太阳能电池（IPTSCs）是攻破效力瓶颈跟处理稳固性成绩的有盼望的候选者。但是，因为锡离子引诱的较差的薄膜构成跟深阱状况，在制备双端（2T）IPTSC方面依然存在挑衅。研讨者采取对甲苯磺酰肼（PTSH）的配体退化（LE）战略来调理无机窄带隙（NBG）钙钛矿中的薄膜构成并打消深层圈套，从而胜利开辟了2T IPTSC。IPTSC在最年夜功率点跟踪下存在出色的耐用性，在65°C跟85°C下分辨坚持80%的初始效力1510小时跟800小时。研讨说明了LE有意应用无机NBG钙钛矿成长的多种感化，无望为开辟高效稳固的IPTSC供给有洞察力的领导。▲ Abstract：All-inorganic perovskites prepared by substituting the organic cations (for example, methylammonium and formamidinium) with inorganic cations (for example, Cs+) are effective concepts to enhance the long-term photostability and thermal stability of perovskite solar cells (PSCs). Hence, inorganic perovskite tandem solar cells (IPTSCs) are promising candidates for breaking the efficiency bottleneck and addressing the stability issue, too. However, challenges remain in fabricating two-terminal (2T) IPTSCs due to the inferior film formation and deep trap states induced by tin cations. Here a ligand evolution (LE) strategy with p-toluenesulfonyl hydrazide (PTSH) is used to regulate film formation and eliminate deep traps in inorganic narrow-bandgap (NBG) perovskites, enabling the successful development of 2T IPTSCs. IPTSCs are engineered to deliver remarkable durability under maximum power point (MPP) tracking, maintaining 80% of their initial efficiency at 65?°C for 1,510 h and at 85?°C for 800?h. We elucidate that LE deliberately leverages multiple roles for inorganic NBG perovskite growth and anticipate that our study provides an insightful guideline for developing high-efficiency and stable IPTSCs.生物学BiologySleep microstructure organizes memory replay就寝微不雅构造构造影象重放▲ 作者：Hongyu Chang, Wenbo Tang, Annabella M. Wulf, Thokozile Nyasulu, Madison E. Wolf, Antonio Fernandez-Ruiz Azahara Oliva▲ 链接：https://www.nature.com/articles/s41586-024-08340-w▲择要：近来取得的影象在就寝时在海马体中被从新激活，这是坚固影象的第一步。这一进程随同着海马体对先前影象的再激活，这就提出了怎样避免旧的跟近来的、不稳固的影象陈迹之间的烦扰的成绩。实践研讨标明，能够经由过程随机交织的从新激活来坚固多个影象，同时最年夜限制地增加烦扰。另一种说法是，就寝的时光微不雅构造能够在特定的亚状况下增进差别范例影象的从新激活。为了验证这两个假设，研讨者开辟了一种方式，能够同时记载年夜海马群，并经由过程瞳孔丈量法监测天然就寝小鼠的就寝静态。振荡的瞳孔稳定提醒了从前未知的非疾速眼动就寝相干影象进程的微不雅构造。他们发明，在非疾速眼动就寝的瞳孔压缩状况下，近来阅历的影象重播重要产生在锐波荡漾中，而从前的影象重播则优先产生在瞳孔扩大状况下。在瞳孔压缩的非疾速眼动就寝中，抉择性地中止锐波荡漾的闭环会侵害对近来影象的回想，而在瞳孔扩大的亚状况中，同样的操纵对行动不影响。较强的外部高兴输入是瞳孔压缩亚状况的特点，而在瞳孔扩大亚状况下，部分克制的召募较高。因而，非疾速眼动就寝的微不雅构造构造了影象重放，从前的影象跟新的影象在差别的亚状况中被临时分别，分辨由部分跟输入驱念头制支撑。研讨成果标明，年夜脑能够在就寝中多重处置差别的认知进程，以增进不受烦扰的连续进修。▲ Abstract：Recently acquired memories are reactivated in the hippocampus during sleep, an initial step for their consolidation. This process is concomitant with the hippocampal reactivation of previous memories, posing the problem of how to prevent interference between older and recent, initially labile, memory traces. Theoretical work has suggested that consolidating multiple memories while minimizing interference can be achieved by randomly interleaving their reactivation. An alternative is that a temporal microstructure of sleep can promote the reactivation of different types of memories during specific substates. Here, to test these two hypotheses, we developed a method to simultaneously record large hippocampal ensembles and monitor sleep dynamics through pupillometry in naturally sleeping mice. Oscillatory pupil fluctuations revealed a previously unknown microstructure of non-REM sleep-associated memory processes. We found that memory replay of recent experiences dominated in sharp-wave ripples during contracted pupil substates of non-REM sleep, whereas replay of previous memories preferentially occurred during dilated pupil substates. Selective closed-loop disruption of sharp-wave ripples during contracted pupil non-REM sleep impaired the recall of recent memories, whereas the same manipulation during dilated pupil substates had no behavioural effect. Stronger extrinsic excitatory inputs characterized the contracted pupil substate, whereas higher recruitment of local inhibition was prominent during dilated pupil substates. Thus, the microstructure of non-REM sleep organizes memory replay, with previous versus new memories being temporally segregated in different substates and supported by local and input-driven mechanisms, respectively. Our results suggest that the brain can multiplex distinct cognitive processes during sleep to facilitate continuous learning without interference.Synaptic basis of feature selectivity in hippocampal neurons海马神经元特点抉择性的突触基本▲ 作者：Kevin C. Gonzalez, Adrian Negrean, Zhenrui Liao, Satoshi Terada, Guofeng Zhang, Sungmoo Lee, Katalin ócsai, Balázs J. Rózsa, Michael Z. Lin, Franck Polleux Attila Losonczy▲ 链接：https://www.nature.com/articles/s41586-024-08325-9▲ 择要：神经迷信的一个中心成绩是突触可塑性怎样影响行动植物神经元的特点抉择性。海马CA1锥体神经元经由过程构成被称为地位场的空间跟情境抉择性接收野，表现出最明显的特点抉择性情势之一，这是研讨进修跟影象的突触基本的模子。差别情势的突触可塑性被以为是地位场呈现的细胞基质。但是，只管经由数十年的研讨，人们对突触可塑性怎样影响地位场构成跟影象编码的懂得依然无限，这重要是因为缺少东西跟技巧挑衅，无奈在苏醒行动植物的单神经元辨别率上可视化突触可塑性。为懂得决这个成绩，研讨者开辟了一种全光学方式来监测空间导航进程中单个CA1锥体神经元地位场引诱前后树突棘的时空调调和突触分量变更。他们发明了一个时光上错误称的突触可塑性核，这是由地位场引诱四周突触权重的双向修正惹起的。该研讨断定了基底树突跟斜树突之间突触可塑性的巨细跟时光表白的室特异性差别。研讨成果供给了试验证据，证实突触可塑性与海马神经元空间抉择性的疾速呈现有关，而空间抉择性是情景影象的要害先决前提。▲ Abstract：A central question in neuroscience is how synaptic plasticity shapes the feature selectivity of neurons in behaving animals1. Hippocampal CA1 pyramidal neurons display one of the most striking forms of feature selectivity by forming spatially and contextually selective receptive fields called place fields, which serve as a model for studying the synaptic basis of learning and memory. Various forms of synaptic plasticity have been proposed as cellular substrates for the emergence of place fields. However, despite decades of work, our understanding of how synaptic plasticity underlies place-field formation and memory encoding remains limited, largely due to a shortage of tools and technical challenges associated with the visualization of synaptic plasticity at the single-neuron resolution in awake behaving animals. To address this, we developed an all-optical approach to monitor the spatiotemporal tuning and synaptic weight changes of dendritic spines before and after the induction of a place field in single CA1 pyramidal neurons during spatial navigation. We identified a temporally asymmetric synaptic plasticity kernel resulting from bidirectional modifications of synaptic weights around the induction of a place field. Our work identified compartment-specific differences in the magnitude and temporal expression of synaptic plasticity between basal dendrites and oblique dendrites. Our results provide experimental evidence linking synaptic plasticity to the rapid emergence of spatial selectivity in hippocampal neurons, a critical prerequisite for episodic memory.