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<jats:p>Facing the computing demands of Internet of things (IoT) and artificial intelligence (AI), the cost induced by moving the data between the central processing unit (CPU) and memory is the key problem and a chip featured with flexible structural unit, ultra-low power consumption, and huge parallelism will be needed. In-memory computing, a non-von Neumann architecture fusing memory units and computing units, can eliminate the data transfer time and energy consumption while performing massive parallel computations. Prototype in-memory computing schemes modified from different memory technologies have shown orders of magnitude improvement in computing efficiency, making it be regarded as the ultimate computing paradigm. Here we review the state-of-the-art memory device technologies potential for in-memory computing, summarize their versatile applications in neural network, stochastic generation, and hybrid precision digital computing, with promising solutions for unprecedented computing tasks, and also discuss the challenges of stability and integration for general in-memory computing.</jats:p>

<jats:p>Spin–orbit torque (SOT) effect is considered as an efficient way to switch the magnetization and can inspire various high-performance spintronic devices. Recently, topological insulators (TIs) have gained extensive attention, as they are demonstrated to maintain a large effective spin Hall angle (<jats:inline-formula> <jats:tex-math><?CDATA ${\theta }_{{\rm{SH}}}^{{\rm{eff}}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>θ</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">SH</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">eff</mml:mi> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_7_078505_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>), even at room temperature. However, molecular beam epitaxy (MBE), as a precise deposition method, is required to guarantee favorable surface states of TIs, which hinders the prospect of TIs towards industrial application. In this paper, we demonstrate that Bi<jats:sub>2</jats:sub>Te<jats:sub>3</jats:sub> films grown by magnetron sputtering can provide a notable SOT effect in the heterostructure with perpendicular magnetic anisotropy CoTb ferrimagnetic alloy. By harmonic Hall measurement, a high SOT efficiency (8.7 ± 0.9 Oe/(10<jats:sup>9</jats:sup> A/m<jats:sup>2</jats:sup>)) and a large <jats:inline-formula> <jats:tex-math><?CDATA ${\theta }_{{\rm{SH}}}^{{\rm{eff}}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>θ</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">SH</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">eff</mml:mi> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_7_078505_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> (3.3±0.3) are obtained at room temperature. Besides, we also observe an ultra-low critical switching current density (9.7×10<jats:sup>9</jats:sup> A/m<jats:sup>2</jats:sup>). Moreover, the low-power characteristic of the sputtered Bi<jats:sub>2</jats:sub>Te<jats:sub>3</jats:sub> film is investigated by drawing a comparison with different sputtered SOT sources. Our work may provide an alternative to leverage chalcogenides as a realistic and efficient SOT source in future spintronic devices.</jats:p>

<jats:p>To promote the application of far-infrared technology, functional far-infrared devices with high performance are needed. Here, we propose a design scheme to develop a wide-incident-angle far-infrared absorber, which consists of a periodically semicircle-patterned graphene sheet, a lossless inter-dielectric spacer and a gold reflecting film. Under normal incidence for both TE- and TM-polarization modes, the bandwidth of 90% absorption of the proposed far-infrared absorber is ranging from 6.76 THz to 11.05 THz. The absorption remains more than 90% over a 4.29-THz broadband range when the incident angle is up to 50° for both TE- and TM-polarization modes. The peak absorbance of the absorber can be flexibly tuned from 10% to 100% by changing the chemical potential from 0 eV to 0.6 eV. The tunable broadband far-infrared absorber has promising applications in sensing, detection, and stealth objects.</jats:p>

<jats:p>We report a broadband terahertz time-domain spectroscopy (THz-TDS) which enables twenty vibrational modes of adenosine nucleoside to be resolved in a wide frequency range of 1–20 THz. The observed spectroscopic features of adenosine are in good agreement with the published spectra obtained using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. This much extended bandwidth leads to enhanced material characterization capability as it provides spectroscopic information on both intra- and inter-molecular vibrations. In addition, we also report a low-cost frequency modulation continuous wave (FMCW) imaging system which has a fast measurement speed of 40000 waveforms per second. Cross-sectional imaging capability through cardboard has also been demonstrated using its excellent penetration capability at a frequency range of 76–81 GHz. We anticipate that the integration of these two complementary imaging technologies would be highly desirable for many real-world applications because it provides both spectroscopic discrimination and penetration capabilities in a single instrument.</jats:p>

<jats:p>Polarization conversion is a very important electromagnetic wave manipulation method. In this paper, we investigate a high-efficiency linear-to-circular polarization and cross-polarization converter by utilizing coding metasurface. The coding particle consists of top layer metal pattern and bottom metal plate sandwiched with square F4B dielectric, which can manipulate the linear-to-circular polarization and cross-polarization converter of the reflected wave simultaneously. In the terahertz frequency range of 1.0 THz–2.0 THz, the reflection magnitudes reach approximately 90% and the axial ratio is less than 3 dB. The proposed polarization converter may lead to advances in a variety of applications such as security, microscopy, information processing, stealth technology, and data storage.</jats:p>

<jats:p>The terahertz (THz) resonance, chirality, and polarization conversion properties of a double-layer chiral metasurface have been experimentally investigated by THz time domain spectroscopy system and polarization detection method. The special symmetric geometry of each unit cell with its adjacent cells makes a strong chiral electromagnetic response in this metasurface, which leads to a strong polarization conversion effect. Moreover, compared with the traditional THz transmission resonance sensing for film thickness, the polarization sensing characterized by polarization elliptical angle (PEA) and polarization rotation angle (PRA) shows a better <jats:italic>Q</jats:italic> factor and figure of merit (FoM). The results show that the <jats:italic>Q</jats:italic> factors of the PEA and PRA reach 43.8 and 49.1 when the interval film is 20 μm, while the <jats:italic>Q</jats:italic> factor of THz resonance sensing is only 10.6. And these PEA and PRA can play a complementary role to obtain a double-parameter sensing method with a higher FoM, over 4 times than that of resonance sensing. This chiral metasurface and its polarization sensing method provide new ideas for the development of high-efficiency THz polarization manipulation, and open a window to the high sensitive sensing by using THz polarization spectroscopy.</jats:p>

<jats:p>Coper thiocyanate (CuSCN) is generally considered as a very hopeful inorganic hole transport material (HTM) in semitransparent perovskite solar cells (ST-PSCs) because of its low parasitic absorption, high inherent stability, and low cost. However, the poor electrical conductivity and low work function of CuSCN lead to the insufficient hole extraction and large open-circuit voltage loss. Here, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) is employed to improve conductivity of CuSCN and band alignment at the CuSCN/perovskite (PVK) interface. As a result, the average power conversion efficiency (PCE) of PSCs is boosted by ≈ 11%. In addition, benefiting from the superior transparency of p-type CuSCN HTMs, the prepared bifacial semitransparent n–i–p planar PSCs demonstrate a maximum efficiency of 14.8% and 12.5% by the illumination from the front side and back side, respectively. We believe that this developed CuSCN-based ST-PSCs will promote practical applications in building integrated photovoltaics and tandem solar cells.</jats:p>

<jats:p>We investigate the quantum to classical transition induced by two-particle interaction via a system of periodically kicked particles. The classical dynamics of particle 1 is almost unaffected in condition that its mass is much larger than that of particle 2. Interestingly, such classically weak influence leads to the quantum to classical transition of the dynamical behavior of particle 1. Namely, the quantum diffusion of this particle undergoes the transition from dynamical localization to the classically chaotic diffusion with the decrease of the effective Planck constant <jats:italic>ℏ</jats:italic> <jats:sub>eff</jats:sub>. The behind physics is due to the growth of entanglement in the system. The classically very weak interaction leads to the exponential decay of purity in condition that the classical dynamics of external degrees freedom is strongly chaotic.</jats:p>

<jats:p>We show that it is possible to simulate an anyon by a trapped atom which possesses an induced electric dipole moment in the background of electric and magnetic fields in a specific configuration. The electric and magnetic fields we applied contain a magnetic and two electric fields. We find that when the atom is cooled down to the limit of the negligibly small kinetic energy, the atom behaves like an anyon because its angular momentum takes fractional values. The fractional part of the angular momentum is determined by both the magnetic and one of the electric fields. Roles electric and magnetic fields played are analyzed.</jats:p>

<jats:p>Testing the extreme weak gravitational forces between torsion pendulum and surrounding objects will indicate new physics which attracts many interests. In these measurements, the fiber alignment plays a crucial role in fulfilling high precision placement measurement, especially in measuring the deviation between the fiber and source mass or other objects. The traditional way of the fiber alignment requires to measure the component of the pendulum body and then transfer to the torsion fiber by some complicated calculations. A new method is reported here by using a CCD camera to get the projection image of the torsion fiber, which is a direct and no-contact measurement. Furthermore, the relative position change of the torsion fiber can also be monitored during the experiment. In our experiment, the alignment between the fiber and the center of the turntable has been operated as an example. Our result reaches the accuracy of several micrometers which is higher than the previous method.</jats:p>