Matter-wave interferometers with spin quantum states are attractive in quantum manipulation and precision measurements. Here, five spatial interference patterns corresponding to the full spin states are observed in each run of the experiment, by the combination of the Majorana transition according to the exponential modulation of the magnetic field pulse decline curve and radio frequency coupling among multiple magnetic sub-states. Compared to the realization of two Majorana transitions, the interference fringe for the magnetic field insensitive state also has a higher contrast. After spatially overlapping the full magnetic sub-state interference patterns dozens of times in consecutive experimental measurements, clear fringes are still observed, indicating the great stability of the relative phases of different components. This indicates the potential to achieve an interferometer with multiple spin clocks.

We study the fringe visibility and the which-path information (WPI) of a general Mach–Zehnder interferometer with an asymmetric beam splitter (BS). A minimum error measurement in the detector is used to extract the WPI. Both the fringe visibility $V$ and the WPI $I_{\rm path}$ are affected by the initial state of the photon and the second asymmetric BS. The condition in which the WPI takes the maximum is obtained. The complementarity relationship $V^{2}+I_{\rm path}^{2}\leq 1$ is found, and the conditions for equality are also presented.

Considering the influences of collective dephasing, multilocal qutrit-flip, local qutrit-flip, and the combination of global mixed noise, we study the dynamics of entanglement and the phenomenon of distillability of sudden death (DSD) in a qutrit-qutrit system under various decoherent noises. It is shown that the system always undergoes DSD when it interacts with multilocal and local qutrit-flip noise, and the time-determined bound entangled state is more dependent on different noises. Comparing with the cases of global mixed and collective dephasing noise, we conclude that the qutrit-flip noise is responsible for the DSD.

Three Alice–Bob Boussinesq (ABB) nonlocal systems with shifted parity ($\hat{P}_{\rm s}$), delayed time reversal ($\hat{T}_{\rm d}$) and $\hat{P}_{\rm s}\hat{T}_{\rm d}$ nonlocalities are investigated. The multi-soliton solutions of these models are systematically found from the $\hat{P}_{\rm s}$, $\hat{T}_{\rm d}$ and $\hat{P}_{\rm s}\hat{T}_{\rm d}$ symmetry reductions of a coupled local Boussinesq system. The result shows that for ABB equations with $\hat{P}_{\rm s}$ and/or $\hat{T}_{\rm d}$ nonlocality, an odd number of solitons is prohibited. The solitons of the $\hat{P}_{\rm s}$ nonlocal ABB and $\hat{T}_{\rm d}$ nonlocal ABB equations must be paired, while any number of solitons is allowed for the $\hat{P}_{\rm s}\hat{T}_{\rm d}$ nonlocal ABB system. $t$-breathers, $x$-breathers and rogue waves exist for all three types of nonlocal ABB system. In particular, different from classical local cases, the first-order rogue wave can have not only four leaves but also five and six leaves.

FUNDAMENTAL AREAS OF PHENOMENOLOGY(INCLUDING APPLICATIONS)

We theoretically investigate single-photon polarization conversion via scattering by an atom with ${\Lambda}$ configuration coupled to a semi-infinite waveguide and discuss the two cases in which the ${\Lambda}$ system is non-degenerated and degenerated. By applying the hard-wall boundary condition of the semi-infinite waveguide, it is found that single-photon polarization conversion can be realized with unit probability for both cases under the ideal condition. Together with the polarization conversion, the frequency conversion of a single photon can also be realized with unit probability in the ideal case if the ${\Lambda}$ system is not degenerated.

Nanosecond pulse generation in an erbium-doped fiber laser (EDFL) passively mode-locked by a silver nanoparticle (SNP)-based saturable absorber (SA) is experimentally demonstrated. The SA is fabricated by depositing a nanosized SNP layer onto the surface of polyvinyl alcohol film through the thermal evaporation process. By inserting the SA into an EDFL cavity, stable mode-locked operation is achieved at 1561.5 nm with the maximum pulse energy up to 52.3 nJ. The laser operates at a pulse repetition frequency of 1.0 MHz with a pulse width of 202 ns. These results suggest that SNPs could be developed as an effective SA for mode-locking pulse generation.

The dependence of harmonic emission from a solid on the carrier envelope phase (CEP) is discussed by numerically solving the time-dependent Schrödinger equation. The harmonic spectra periodically exhibit three distinct oscillating structures, which indicate the different dependences of the cutoff energies on the CEP. Furthermore, with time-dependent population imaging and the populations of different energy bands, the underlying physical mechanism is explored.

The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication process on the AWG is achieved by the design of bi-level tapers. The wavelength tuning of the AWG is achieved according to the thermo-optic effect of silicon, and uniform heating of the silicon waveguide layer is achieved by optimizing the heater design. The fabricated AWG shows a minimum crosstalk of 16 dB, a maximum insertion loss of 3.91 dB and a wavelength tuning efficiency of 8.92 nm/W, exhibiting a $\sim $8 dB improvement of crosstalk, $\sim $2.1 dB improvement of insertion loss and $\sim $5 nm/W improvement of wavelength tuning efficiency, compared to our previous reported results.

CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES

The mechanical properties of formamidinium halide perovskites FABX$_{3}$ (FA=CH(NH$_{2})_{2}$; B=Pb, Sn; X=Br, I) are systematically investigated using first-principles calculations. Our results reveal that FABX$_{3}$ perovskites possess excellent mechanical flexibility, ductility and strong anisotropy. We shows that the planar organic cation FA$^{+}$ has an important effect on the mechanical properties of FABX$_{3}$ perovskites. In addition, our results indicate that (i) the moduli (bulk modulus $B$, Young's modulus $E$, and shear modulus $G$) of FABBr$_{3}$ are larger than those of FABI$_{3}$ for the same B atom, and (ii) the moduli of FAPbX$_{3}$ are larger than those of FASnX$_{3}$ for the same halide atom. The reason for the two trends is demonstrated by carefully analyzing the bond strength between B and X atoms based on the projected crystal orbital Hamilton population method.

Superconductivity and its relationship with strain remains elusive in the monolayer FeSe superconductor. Based on first-principles calculations and model studies, we investigate the magnetic properties of FeSe and FeTe monolayers and find that tensile strain induces changes to magnetic phases for both materials. Furthermore, we reveal that electron doping will decrease the difference of effective magnetic interactions between the $a$ and $b$ directions in an FeSe monolayer and hence suppress its nematicity. We suggest that the overall effect of tensile strain combined with electron doping hinders the appearance of both magnetic and nematic orders in an FeSe monolayer, which paves the way for the emergence of superconductivity.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

The effect of temperature on the characteristics of gallium nitride (GaN) Schottky barrier diodes (SBDs) with TiN and Ni anodes is evaluated. With increasing the temperature from 25 to 175$^{\circ}\!$C, reduction of the turn-on voltage and increase of the leakage current are observed for both GaN SBDs with TiN and Ni anodes. The performance after thermal treatment shows much better stability for SBDs with TiN anode, while those with Ni anode change due to more interface states. It is found that the leakage currents of the GaN SBDs with TiN anode are in accord with the thermionic emission model whereas those of the GaN SBDs with Ni anode are much higher than the model. The Silvaco TCAD simulation results show that phonon-assisted tunneling caused by interface states may lead to the instability of electrical properties after thermal treatment, which dominates the leakage currents for GaN SBDs with Ni anode. Compared with GaN SBDs with Ni anode, GaN SBDs with TiN anode are beneficial to the application in microwave power rectification fields due to lower turn-on voltage and better thermal stability.

We report a systematic study on magnetotransport properties of the single crystal of cadmium (Cd). When the applied magnetic field $B$ is perpendicular to the current $I$, the resistivities for both directions ($I\parallel a$, $I \parallel c$) show field induced metal-to-insulator-like transitions. The isothermal magnetoresistance (MR) at low temperatures increases approximately as the square of the magnetic field without any sign of saturation, and reaches up to 1140000% and 58000% at $T=2$ K and $B=9$ T for $I\parallel a$ and $I\parallel c$, respectively. As the magnetic field rotates to parallel to the current, no sign of negative MR is observed for $I\parallel a$, while an obvious negative MR appears up to $-$70% at 2 K and 9 T for the current flowing along the $c$-axis, and the negative longitudinal MR shows a strong dependence of the electrode position on the single crystal. These results suggest that the negative longitudinal MR is caused by the dislocations formed in the process of crystal growing along the $c$-axis. Further studies are needed to clarify this point.

Absorption coefficient is a physical parameter to describe electromagnetic energy absorption of materials, which is closely related to solar cells and photodetectors. We grow a series of positive-intrinsic-negative (PIN) structures on silicon wafer by a gas source molecule beam epitaxy system and the investigate the absorption coefficient through the photovoltaic processes in detail. It is found that the absorption coefficient is enhanced by one order and can be tuned greatly through the thickness of the intrinsic layer in the PIN structure, which is also demonstrated by the 730-nm-wavelength laser irradiation. These results cannot be explained by the traditional absorption theory. We speculate that there could be some uncovered mechanism in this system, which will inspire us to understand the absorption process further.

A double-tapered AlGaN electron blocking layer (EBL) is proposed to apply in a deep ultraviolet semiconductor laser diode. Compared with the inverse double-tapered EBL, the laser with the double-tapered EBL shows a higher slope efficiency, which indicates that effective enhancement in the transportation of electrons and holes is achieved. Particularly, comparisons among the double-tapered EBL, the inverse double-tapered EBL, the single-tapered EBL and the inverse single-tapered EBL show that the double-tapered EBL has the best performance in terms of current leakage.

We demonstrate theoretically the anisotropic quantum transport of electrons through an electric field on monolayer and multilayer phosphorene. Using the long-wavelength Hamiltonian with continuum approximation, we find that the transmission probability for transport through an electric field is an oscillating function of incident angle, electric field intensity, as well as the incident energy of electrons. By tuning the electric field intensity and incident angle, the channels can be transited from opaque to transparent. The conductance through the quantum waveguides depends sensitively on the transport direction because of the anisotropic effective mass, and the anisotropy of the conductance can be tuned by the electric field intensity and the number of layers. These behaviors provide us an efficient way to control the transport of phosphorene-based microstructures.

A kind of n-type HoF$_{3}$-doped zinc oxide-based transparent conductive film has been developed by electron beam evaporation and studied under thermal annealing in air and vacuum at temperatures 100–500$^{\circ}\!$C. Effective substitutional dopings of F to O and Ho to Zn are realized for the films with smooth surface morphology and average grain size of about 50 nm. The hall mobility, electron concentration, resistivity and work function for the as-deposited films are 47.89 cm$^{2}$/Vs, 1.39$\times 10^{20}$ cm$^{-3}$, $9.37\times 10^{-4}$ $\Omega$$\cdot$cm and 5.069 eV, respectively. In addition, the average transmittance in the visible region (400–700 nm) approximates to 87%. The HoF$_{3}$:ZnO films annealed in air and vacuum can retain good optoelectronic properties under 300$^{\circ}\!$C, thereinto, more stable electrical properties can be found in the air-annealed films than in the vacuum-annealed films, which is assumed to be a result of improved nano-crystalline lattice quality. The optimized films for most parameters can be obtained at 200$^{\circ}\!$C for the air-annealing case and at room temperature for the vacuum annealing case. The advisable optoelectronic properties imply that HoF$_{3}$:ZnO can facilitate carrier injection and has promising applications in energy and light sources as transparent electrodes.

TlBa$_{2}$Ca$_{2}$Cu$_{3}$O$_{9}$ (Tl-1223) films have promising applications due to their high critical temperature and strong magnetic flux pinning. Nevertheless, the preparation of pure phase Tl-1223 film is still a challenge. We successfully fabricate Tl-1223 thin films on LaAlO$_{3}$ (001) substrates using dc magnetic sputtering and a post annealing two-step method in argon atmosphere. The crystallization temperature of Tl-1223 films in argon is reduced by 100$^{\circ}\!$C compared to that in oxygen. This greatly reduces the volatilization of Tl and improves the surface morphology of films. The lower annealing temperature can effectively improve the repeatability of the Tl-1223 film preparation. In addition, pure Tl-1223 phase can be obtained in a broad temperature zone, from 790$^{\circ}\!$C to 830$^{\circ}\!$C. In our study, the films show homogenous and dense surface morphology using the presented method. The best critical temperature of Tl-1223 films is characterized to be 110 K, and the critical current $J_{\rm c}$ (77 K, 0 T) is up to $2.13\times 10^{6}$ A/cm$^{2}$.

Transition metal dichalcogenides, featuring layered structures, have aroused enormous interest as a platform for novel physical phenomena and a wide range of potential applications. Among them, special interest has been placed upon WTe$_{2}$ and MoTe$_{2}$, which exhibit non-trivial topology both in single layer and bulk as well as pressure induced or enhanced superconductivity. We study another distorted 1T material NbTe$_{2}$ through systematic electrical transport measurements. Intrinsic superconductivity with onset transition temperature ($T_{\rm c}^{\rm onset}$) up to 0.72 K is detected where the upper critical field ($H_{\rm c}$) shows unconventional quasi-linear behavior, indicating spin-orbit coupling induced p-wave paring. Furthermore, a general model is proposed to fit the angle-dependent magnetoresistance, which reveals the Fermi surface anisotropy of NbTe$_{2}$. Finally, non-saturating linear magnetoresistance up to 50 T is observed and attributed to the quantum limit transport.

The Majorana zero mode (MZM), which manifests as an exotic neutral excitation in superconductors, is the building block of topological quantum computing. It has recently been found in the vortices of several iron-based superconductors as a zero-bias conductance peak in tunneling spectroscopy. In particular, a clean and robust MZM has been observed in the cores of free vortices in (Li$_{0.84}$Fe$_{0.16}$)OHFeSe. Here using scanning tunneling spectroscopy, we demonstrate that Majorana-induced resonant Andreev reflection occurs between the STM tip and this zero-bias bound state, and consequently, the conductance at zero bias is quantized as $2e^{2}/h$. Our results present a hallmark signature of the MZM in the vortex of an intrinsic topological superconductor, together with its intriguing behavior.

We present low-temperature magnetization, magnetoresistance and specific heat measurements on the Kondo lattice compound CePt$_{3}$P under applied magnetic fields up to 9.0 T. At zero field, CePt$_{3}$P exhibits a moderately enhanced Sommerfeld coefficient of electronic specific heat $\gamma_{\rm Ce}=86$ mJ/mol$\cdot$K$^{2}$ as well as two successive magnetic transitions of Ce 4$f$ moments: an antiferromagnetic ordering at $T_{\rm N1}=3.0$ K and a spin reorientation at $T_{\rm N2}=1.9$ K. The value of $T_{\rm N1}$ shifts to lower temperature as magnetic field increases, and it is ultimately suppressed around $B_{\rm c}\sim 3.0$ T at 1.5 K. No evidence of non-Fermi liquid behavior is observed around $B_{\rm c}$ down to the lowest temperature measured. Moreover, $\gamma$ decreases monotonously with increasing the magnetic field. On the other hand, the electrical resistivity shows an anomalous temperature dependence $\rho\propto T^{n}$ with the exponent $n$ decreasing monotonously from $\sim$2.6 around $B_{\rm c}$ down to $\sim$1.7 for $B=9.0$ T. The $T$–$B$ phase diagram constructed from the present experimental results of CePt$_{3}$P does not match the quantum criticality scenario of heavy fermion systems.