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<jats:p>As a new type of quantum state of matter hosting low energy relativistic quasiparticles, Weyl semimetals (WSMs) have attracted significant attention for scientific community and potential quantum device applications. In this study, we present a comprehensive investigation of the structural, magnetic, and transport properties of noncentrosymmetric <jats:italic>R</jats:italic>AlSi (<jats:italic>R</jats:italic> = Sm, Ce), which have been predicted to be new magnetic WSM candidates. Both samples exhibit nonsaturated magnetoresistance, with about 900% and 80% for SmAlSi and CeAlSi, respectively, at temperature of 1.8 K and magnetic field of 9 T. The carrier densities of SmAlSi and CeAlSi exhibit remarkable change around magnetic transition temperatures, signifying that the electronic states are sensitive to the magnetic ordering of rare-earth elements. At low temperatures, SmAlSi reveals prominent Shubnikov-de Haas oscillations associated with the nontrivial Berry phase. High-pressure experiments demonstrate that the magnetic order is robust and survival under high pressure. Our results would yield valuable insights into WSM physics and potentials in applications to next-generation spintronic devices in the <jats:italic>R</jats:italic>AlSi (<jats:italic>R</jats:italic> = Sm, Ce) family.</jats:p>

<jats:p>We investigate the spin Hall magnetoresistance (SMR) in all-antiferromagnetic heterostructures <jats:italic>α</jats:italic>-Fe<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>/Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> with Pt contacts. When the temperature is ultralow (&lt; 50 K), the spin current generated in the Pt layer cannot be transmitted through Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> (<jats:italic>t</jats:italic> = 4 nm), and the SMR is near zero. Meanwhile, when the temperature is higher than the spin fluctuation temperature <jats:italic>T</jats:italic> <jats:sub>F</jats:sub> (≈ 50 K) of Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> and lower than its Néel temperature <jats:italic>T</jats:italic> <jats:sub>N</jats:sub> (≈ 300 K), the spin current goes through the Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> layer and is reflected at the <jats:italic>α</jats:italic>-Fe<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>/Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> interface; an antiferromagnetic (negative) SMR is observed. As temperature increases higher than <jats:italic>T</jats:italic> <jats:sub>N</jats:sub>, paramagnetic (positive) SMR mainly arises from the spin current reflection at the Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>/Pt interface. The transition temperatures from negative to positive SMR are enhanced with increasing Cr<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> layer thickness, accompanied by the absence of SMR signals when <jats:italic>t</jats:italic> = 10 nm. Such a tunable SMR builds a bridge between spin transport and structures. It also enriches antiferromagnetic spintronics.</jats:p>

<jats:p>Recently, magnetism in two-dimensional (2D) van der Waals (vdW) materials has attracted wide interests. It is anticipated that these materials will stimulate discovery of new physical phenomena and novel applications. The capability to quantitatively measure the magnetism of 2D magnetic vdW materials is essential to understand these materials. Here we report on quantitative measurements of ferromagnetic-to-paramagnetic phase transition of an atomically thin (down to 11 nm) vdW magnet, namely CrBr<jats:sub>3</jats:sub>, with a Curie point of 37.5 K. This experiment demonstrates that surface magnetism can be quantitatively investigated, which is useful for a wide variety of potential applications.</jats:p>

<jats:p>Nonpolar (<jats:inline-formula> <jats:tex-math><?CDATA $11\bar{2}0$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>11</mml:mn> <mml:mover accent="true"> <mml:mn>2</mml:mn> <mml:mo>¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_39_4_048101_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>) plane In<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Ga<jats:sub>1−<jats:italic>x</jats:italic> </jats:sub>N epilayers comprising the entire In content (<jats:italic>x</jats:italic>) range were successfully grown on nanoscale GaN islands by metal-organic chemical vapor deposition. The structural and optical properties were studied intensively. It was found that the surface morphology was gradually smoothed when <jats:italic>x</jats:italic> increased from 0.06 to 0.33, even though the crystalline quality was gradually declined, which was accompanied by the appearance of phase separation in the In<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Ga<jats:sub>1−<jats:italic>x</jats:italic> </jats:sub>N layer. Photoluminescence wavelengths of 478 and 674 nm for blue and red light were achieved for <jats:italic>x</jats:italic> varied from 0.06 to 0.33. Furthermore, the corresponding average lifetime (<jats:italic>τ</jats:italic> <jats:sub>1/<jats:italic>e</jats:italic> </jats:sub>) of carriers for the nonpolar InGaN film was decreased from 406 ps to 267 ps, indicating that a high-speed modulation bandwidth can be expected for nonpolar InGaN-based light-emitting diodes. Moreover, the bowing coefficient (<jats:italic>b</jats:italic>) of the (<jats:inline-formula> <jats:tex-math><?CDATA $11\bar{2}0$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>11</mml:mn> <mml:mover accent="true"> <mml:mn>2</mml:mn> <mml:mo>¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_39_4_048101_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>) plane InGaN was determined to be 1.91 eV for the bandgap energy as a function of <jats:italic>x</jats:italic>.</jats:p>

<jats:p>As one of the most promising Kitaev quantum-spin-liquid (QSL) candidates, <jats:italic>α</jats:italic>-RuCl<jats:sub>3</jats:sub> has received a great deal of attention. However, its ground state exhibits a long-range zigzag magnetic order, which defies the QSL phase. Nevertheless, the magnetic order is fragile and can be completely suppressed by applying an external magnetic field. Here, we explore the evolution of magnetic excitations of <jats:italic>α</jats:italic>-RuCl<jats:sub>3</jats:sub> under an in-plane magnetic field, by carrying out inelastic neutron scattering measurements on high-quality single crystals. Under zero field, there exist spin-wave excitations near the <jats:italic>M</jats:italic> point and a continuum near the <jats:italic>Γ</jats:italic> point, which are believed to be associated with the zigzag magnetic order and fractional excitations of the Kitaev QSL state, respectively. By increasing the magnetic field, the spin-wave excitations gradually give way to the continuous excitations. On the verge of the critical field <jats:italic>μ</jats:italic> <jats:sub>0</jats:sub> <jats:italic>H</jats:italic> <jats:sub>c</jats:sub> = 7.5 T, the former ones vanish and only the latter ones are left, indicating the emergence of a pure QSL state. By further increasing the field strength, the excitations near the <jats:italic>Γ</jats:italic> point become more intense. By following the gap evolution of the excitations near the <jats:italic>Γ</jats:italic> point, we are able to establish a phase diagram composed of three interesting phases, including a gapped zigzag order phase at low fields, possibly gapless QSL phase near <jats:italic>μ</jats:italic> <jats:sub>0</jats:sub> <jats:italic>H</jats:italic> <jats:sub>c</jats:sub>, and gapped partially polarized phase at high fields. These results demonstrate that an in-plane magnetic field can drive <jats:italic>α</jats:italic>-RuCl<jats:sub>3</jats:sub> into a long-sought QSL state near the critical field.</jats:p>

<jats:p>We explore the exceptional point (EP) induced phase transition and amplitude/phase modulation in thermal diffusion systems. We start from the asymmetric coupling double-channel model, where the temperature field is unbalanced in the amplitude and locked in the symmetric phase. By extending into the one-dimensional tight-binding non-Hermitian lattice, we study the convection-driven phase locking and the asymmetric-couplinginduced diffusive skin effect with the high-order EPs in static systems. Combining convection and asymmetric couplings, we further show the phase-locking diffusive skin effect. Our work reveals the mechanism of controlling both the amplitude and phase of temperature fields in thermal coupling systems and has potential applications in non-Hermitian topology in thermal diffusion.</jats:p>

<jats:p>We demonstrate the <jats:italic>in situ</jats:italic> growth of ultra-thin InAs nanowires with an epitaxial Al film by molecular-beam epitaxy. Our InAs nanowire diameter (∼30 nm) is much thinner than before (∼100 nm). The ultra-thin InAs nanowires are pure phase crystals for various different growth directions. Transmission electron microscopy confirms an atomically abrupt and uniform interface between the Al shell and the InAs wire. Quantum transport study on these devices resolves a hard induced superconducting gap and 2<jats:italic>e</jats:italic>-periodic Coulomb blockade at zero magnetic field, a necessary step for future Majorana experiments. By reducing wire diameter, our work presents a promising route for reaching fewer sub-band regime in Majorana nanowire devices.</jats:p>

<jats:p>In quantum information technology, crucial information is regularly encoded in different quantum states. To extract information, the identification of one state from the others is inevitable. However, if the states are non-orthogonal and unknown, this task will become awesomely tricky, especially when our resources are also limited. Here, we introduce the quantum stochastic neural network (QSNN), and show its capability to accomplish the binary discrimination of quantum states. After a handful of optimizing iterations, the QSNN achieves a success probability close to the theoretical optimum, no matter whether the states are pure or mixed. Other than binary discrimination, the QSNN is also applied to classify an unknown set of states into two types: entangled ones and separable ones. After training with four samples, it can classify a number of states with acceptable accuracy. Our results suggest that the QSNN has the great potential to process unknown quantum states in quantum information.</jats:p>