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<jats:p>As the main distribution place of deep-level defects and the entrance of water, the interface is critical to determining both the power conversion efficiency (PCE) and the stability of perovskite solar cells (PSCs). Suitable interface design can dramatically passivate interface defects and optimize energy level alignment for suppressing the nonradiative recombination and effectively extracting the photogenerated carriers towards higher PCE. Meanwhile, a proper interface design can also block the interface diffusion of ions for high operational stability. Therefore, interface modification is of great significance to make the PSCs more efficient and stable. Upon optimized material choices, the three-dimensional halide perovskite graded junction layer, low-dimensional halide perovskite interface layer and organic salt passivation layer have been constructed on perovskite films for superior PSCs, yet a systematic review of them is missing. Thus, a guide and summary of recent advances in modulating the perovskite films interface is necessary for the further development of more efficient interface modification.</jats:p>

<jats:p>MXenes are a new type of two-dimensional carbides with rich physical and chemical properties. The physics of MXenes, and thus the applications, are dominated by surface functional groups. Herein, the effects of different terminations (O, S, Se, Te) on the geometric and electronic properties of Nb<jats:sub>2</jats:sub>C MXenes were studied <jats:italic>via</jats:italic> density functional theory (DFT) calculations. Three adsorption sites were examined to determine the most stable configurations. The results showed that both the types and the positions of surface functional groups influence the geometric stability and physical characters of Nb<jats:sub>2</jats:sub>C. The S and Se terminations make the Nb<jats:sub>2</jats:sub>C MXenes to be semiconductor, while Nb<jats:sub>2</jats:sub>C MXenes with other terminations (O, Te) are conductor. The electron location function, density of states, Bader charge distribution, and the projected crystal orbital Hamilton population were conducted to explain the origin of adsorption stability and electronic nature difference. Our results provide a fundamental understanding about the effects of surface terminations on the intrinsic stability and electronic properties of Nb<jats:sub>2</jats:sub>C MXenes.</jats:p>

<jats:p>The two-dimensional (2D) materials with nodal line band crossing have been attracting great research interest. However, it remains a challenge to find high-stable nodal line structure in 2D systems. Herein, based on the first-principles calculations and theoretical analysis, we propose that monolayer B<jats:sub>6</jats:sub>O possesses symmetry protected Dirac nodal line (DNL) state, with its Fermi velocity of 10<jats:sup>6</jats:sup> m/s in the same order of magnitude as that of graphene. The origin of DNL fermions is induced by coexistence of time-reversal symmetry and inversion symmetry. A two-band tight-binding model is further given to understand the mechanism of DNL. Considering its robustness against spin–orbit coupling (SOC) and high structural stability, these results suggest monolayer B<jats:sub>6</jats:sub>O as a new platform for realizing future high-speed low-dissipation devices.</jats:p>

<jats:p>Introducing metal thin films on two-dimensional (2D) material may present a system to possess exotic properties due to reduced dimensionality and interfacial effects. We deposit Pb islands on single-crystalline graphene on a Ge(110) substrate and studied the nano- and atomic-scale structures and low-energy electronic excitations with scanning tunneling microscopy/spectroscopy (STM/STS). Robust quantum well states (QWSs) are observed in Pb(111) islands and their oscillation with film thickness reveals the isolation of free electrons in Pb from the graphene substrate. The spectroscopic characteristics of QWSs are consistent with the band structure of a free-standing Pb(111) film. The weak interface coupling is further evidenced by the absence of superconductivity in graphene in close proximity to the superconducting Pb islands. Accordingly, the Pb(111) islands on graphene/Ge(110) are free-standing in nature, showing very weak electronic coupling to the substrate.</jats:p>

<jats:p>With its commercialization, the second-generation (2G) high temperature superconducting (HTS) RE–Ba–Cu–O (REBCO, RE is rare earth) tape is extensively applied to the superconducting magnets in the high magnetic fields. However, unlike low temperature superconducting (LTS) magnets, the HTS magnet cannot operate in the persistent current mode (PCM) due to the immature superconducting soldering technique. In this paper, an exciting method for two HTS sub-loops, so-called charging and load loops, is proposed by flux pump consisting of exciting coil and controllable thermal switch. Two HTS sub-loops are made of an REBCO tape with two slits. An exciting coil with iron core is located in one sub-loop and is supplied with a triangular waveform current so that magnetic field is generated in another sub-loop. The influence of magnetic flux on induced current in load loop is presented and verified in experiment at 77 K. The relationship between the induced magnetic flux density and the current on the sub-loops having been calibrated, magnetic flux density, and induced current are obtained. The results show that the HTS sub-loops can be excited by a coil with thermal switch and the induced current increases with magnetic flux of exciting coil increasing, which is promising for persistent current operation mode of HTS magnets.</jats:p>

<jats:p>We re-visit the anomalous sign reversal problem in the Hall effect of the sputtered Nb thin films. We find that the anomalous sign reversal in the Hall effect is extremely sensitive to a small tilting of the magnetic field and to the magnitude of the applied current. Large anomalous variations are also observed in the symmetric part of the transverse resistance <jats:italic>R<jats:sub>xy</jats:sub> </jats:italic>. We suggest that the surface current loops on superconducting grains at the edges of the superconducting thin films may be responsible for the Hall sign reversal and the accompanying anomalous effects in the symmetric part of <jats:italic>R<jats:sub>xy</jats:sub> </jats:italic>.</jats:p>

<jats:p>The proximity-coupled superconducting island arrays on a metallic film provide an ideal platform to study the phase transition of vortex states under mutual interactions between the vortex and potential landscape. We have developed a top-down microfabrication process for Nb island arrays on Au film by employing an Al hard mask. A current-induced dynamic vortex Mott transition has been observed under the perpendicular magnetic fields of <jats:italic>f</jats:italic> magnetic flux quantum per unit cell, which is characterized by a dip-to-peak reversal in differential resistance d <jats:italic>V</jats:italic>/d <jats:italic>I</jats:italic> vs. <jats:italic>f</jats:italic> curve with the increasing current. The d <jats:italic>V</jats:italic>/d <jats:italic>I</jats:italic> vs. <jats:italic>I</jats:italic> characteristics show a scaling behavior near the magnetic fields of <jats:italic>f</jats:italic> = 1/2 and <jats:italic>f</jats:italic> = 1, with the critical exponents <jats:italic>ε</jats:italic> of 0.45 and 0.3, respectively, suggesting different universality classes at these two fields.</jats:p>

<jats:p>Superconducting films with the same hole density but different geometric symmetry have been designed and fabricated. The <jats:italic>R</jats:italic>(<jats:italic>H</jats:italic>) curves show obvious periodic oscillations with several dips at fractional matching fields. It is found that the period of the oscillations in the low field is not necessary equal to that derived from the hole density, but consistent with that from the corresponding wire networks when the large disk-like film regions are regarded as nodes. The experimental results of <jats:italic>R</jats:italic>(<jats:italic>H</jats:italic>), <jats:italic>T</jats:italic> <jats:sub>c</jats:sub>(<jats:italic>H</jats:italic>) and <jats:italic>j</jats:italic> <jats:sub>c</jats:sub>(<jats:italic>H</jats:italic>) at fractional matching fields within the first oscillation also support the rationality of considering films with large-diametered hole arrays as wire networks. Our results demonstrate that the connectivity of superconducting films with large-diametered hole arrays plays a more important role in the oscillations of <jats:italic>R</jats:italic>(<jats:italic>H</jats:italic>) curves.</jats:p>

<jats:p>The relationship between charge-density-wave (CDW) and superconductivity (SC), two vital physical phases in condensed matter physics, has always been the focus of scientists’ research over the past decades. Motivated by this research hotspot, we systematically studied the physical properties of the layered telluride chalcogenide superconductors CuIr<jats:sub>2−<jats:italic>x</jats:italic> </jats:sub>Al<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Te<jats:sub>4</jats:sub> (0 ⩽ x ⩽ 0.2). Through the resistance and magnetization measurements, we found that the CDW order was destroyed by a small amount of Al doping. Meanwhile, the superconducting transition temperature (<jats:italic>T</jats:italic> <jats:sub>c</jats:sub>) kept changing with the change of doping amount and rose towards the maximum value of 2.75 K when <jats:italic>x</jats:italic> = 0.075. The value of normalized specific heat jump (Δ <jats:italic>C</jats:italic>/<jats:italic>γ T</jats:italic> <jats:sub>c</jats:sub>) for the highest <jats:italic>T</jats:italic> <jats:sub>c</jats:sub> sample CuIr<jats:sub>1.925</jats:sub>Al<jats:sub>0.075</jats:sub>Te<jats:sub>4</jats:sub> was 1.53, which was larger than the BCS value of 1.43 and showed the bulk superconducting nature. In order to clearly show the relationship between SC and CDW states, we propose a phase diagram of <jats:italic>T</jats:italic> <jats:sub>c</jats:sub> vs. doping content.</jats:p>

<jats:p>The dilute magnetic intermetallic compound (DMIC) is an extended study of the dilute magnetic semiconductor. The giant magnetic effect and room temperature ferromagnetism are induced by doping minor 3d transition metal into <jats:italic>RE</jats:italic>In<jats:sub>3</jats:sub> intermetallic compound. Owing to the metallic processability, the <jats:italic>RE</jats:italic>In<jats:sub>3</jats:sub>-based DMIC might have the potential application as magnetoelectric device. In this review, the structural stability, magnetic and electric transport properties of <jats:italic>RE</jats:italic>In<jats:sub>3 – <jats:italic>x</jats:italic> </jats:sub> <jats:italic>T<jats:sub>x</jats:sub> </jats:italic> (<jats:italic>RE</jats:italic> = rare earth; <jats:italic>T</jats:italic> = Co, Mn, Fe; <jats:italic>x</jats:italic> = 0–0.3) have been systematically summarized and analyzed.</jats:p>