It is found that Prussian Blue nanoparticles (PBNPs) possess a catalase‐like activity to catalyse the breakdown of H2O2 into oxygen (O2) molecules under the neutral conditions (pH = 7.4). Based on this finding, we have developed a new strategy in which PBNPs can be excellent ultrasound (US) and magnetic‐resonance (MR) dual modality imaging contrast agents for H2O2 diagnostics in vitro and in vivo.

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Pristine graphene is strongly diamagnetic. However, graphene with single carbon atom defects could exhibit paramagnetism. Theoretically, the π magnetism induced by the monovacancy in graphene is characteristic of two spin-split density-of-states (DOS) peaks close to the Dirac point. Since its prediction, many experiments have attempted to study this π magnetism in graphene, whereas only a notable resonance peak has been observed around the atomic defects, leaving the π magnetism experimentally elusive. Here, we report direct experimental evidence of π magnetism by using a scanning tunneling microscope. We demonstrate that the localized state of the atomic defects is split into two DOS peaks with energy separations of several tens of meV. Strong magnetic fields further increase the energy separations of the two spin-polarized peaks and lead to a Zeeman-like splitting. Unexpectedly, the effective g factor around the atomic defect is measured to be about 40, which is about 20 times larger than the g factor for electron spins.

A number of quantum Hall isospin ferromagnetic (QHIFM) states have been predicted in the "relativistic" zero Landau level (LL) of graphene monolayer. These states, especially the states at LL filling factor  = 0 of charge-neutral graphene, have been extensively explored in experiment. To date, identification of these high-field broken-symmetry states has mostly relied on macroscopic transport techniques. Here, we study splitting of the zero LL of graphene at partial filling and demonstrate a direct approach by imaging the QHIFM states at atomic scale with a scanning tunneling microscope. At half filling of the zero LL ( = 0), the system is in a spin unpolarized state and we observe a linear magnetic-fieldscaling of valley splitting. Simultaneously, the spin degeneracy in the two valleys is also lifted by the magnetic fields. When the Fermi level lies inside the spinpolarized states (at  = 1 or -1), the spin splitting is dramatically enhanced because of the strong many-body effects. At  = 0, we direct image the wavefunctions of the QHIFM states at atomic scale and observe an interaction-driven density wave featuring a Kekulé distortion, which is responsible for the large gap at charge neutrality point in high magnetic fields.

as 2D superconductivity (SC), [4][5][6][7][8] magnetism, [9][10][11] and possible coexistence of these two, [12][13][14] providing an intriguing platform for multifunctional electronic devices.The carriers in the 2DEL of STObased heterostructures occupy the Ti 3d t 2g orbitals, where the in-plane d xy bands often have a lower energy than the out-ofplane oriented d xz /d yz due to the confinement of these orbitals at the interface. [1,15] Among the systems investigated so far, the epitaxial polar/nonpolar LAO/STO interface has drawn intensive attention and shows a typical carrier density, n s , of ≈4 × 10 13 cm −2 . [4] This high carrier density results in the population of orbitals with both d xy and d xz /d yz symmetry. The occupation of carriers in different subbands has previously been controlled reversibly using electrostatic gating, leading to a versatile tuning of the physical properties of the interface. [16] For example, by back gating the interface through the STO substrate, a Lifshitz transition was revealed at a critical carrier density of n c = 1.7 × 10 13 cm −2 , [6] above which the Fermi level starts to cross the bottom of the d xz /d yz bands. In proximity to n c , superconductivity exhibits a dome-shape as a function of gating voltage The metallic interface between two oxide insulators, such as LaAlO 3 /SrTiO 3 (LAO/STO), provides new opportunities for electronics and spintronics. However, due to the presence of multiple orbital populations, tailoring the interfacial properties such as the ground state and metal-insulator transitions remains challenging. Here, an unforeseen tunability of the phase diagram of LAO/STO is reported by alloying LAO with a ferromagnetic LaMnO 3 insulator without forming lattice disorder and at the same time without changing the polarity of the system. By increasing the Mn-doping level, x, of LaAl 1−x Mn x O 3 / STO (0 ≤ x ≤ 1), the interface undergoes a Lifshitz transition at x = 0.225 across a critical carrier density of n c = 2.8 × 10 13 cm −2 , where a peak T SC ≈255 mK of superconducting transition temperature is observed. Moreover, the LaAl 1−x Mn x O 3 turns ferromagnetic at x ≥ 0.25. Remarkably, at x = 0.3, where the metallic interface is populated by only d xy electrons and just before it becomes insulating, a same device with both signatures of superconductivity and clear anomalous Hall effect (7.6 × 10 12 cm −2 < n s ≤ 1.1 × 10 13 cm −2 ) is achieved reproducibly. This provides a unique and effective way to tailor oxide interfaces for designing on-demand electronic and spintronic devices. Oxide InterfacesThe surface of SrTiO 3 (STO) [1] or its interface to another oxide insulator such as the polar perovskite LaAlO 3 (LAO) [2] or the spinel γ-Al 2 O 3 [3] can host a 2D electron liquid (2DEL). In particular, the 2DEL at LAO/STO interface has been found to exhibit a wide spectrum of emergent phenomena such

We report the first direct measurement of decays of the Λ + c baryon involving the neutron. The 118 analysis is performed using 567 pb −1 of e + e − collision data collected at √ s = 4.599 GeV with the BESIII detector at the BEPCII collider. We observe the decay Λ 188The BESIII detector is a cylindrical detector with a solid-angle coverage of 93% of 4π that operates at the

Twisted bilayer graphene with a twist angle of exactly 30° (30°-TBG) is a unique two-dimensional (2D) van der Waals (vdW) system because of its quasicrystalline nature. Here we report, for the first time, scanning tunneling microscopy (STM) measurements of the quasicrystalline 30°-TBG that was obtained in a controllable way by using transfer-assisted fabrication of a pair of graphene sheets. The quasicrystalline order of the 30°-TBG, showing a 12-fold rotational symmetry, was directly visualized in atomic-resolved STM images. In the presence of high magnetic fields, we observed Landau quantization of massless Dirac fermions, demonstrating that the studied 30°-TBG is a relativistic Dirac fermion quasicrystal. Because of a finite interlayer coupling between the adjacent two layers of the 30°-TBG, a suppression of density-of-state (DOS) at the crossing point between the original and mirrored Dirac cones was observed. Moreover, our measurements also observe strong intervalley scattering in the defect-free quasicrystal, indicating that the electronic properties of the 30°-TBG should be quite different from that of its component: the graphene monolayer.

The organic−inorganic hybrid quasi-two-dimensional (quasi-2D) perovskites have attracted increasing attention for solar cell applications due to their improved moisture stability and excellent optoelectronic properties. To achieve a profound understanding and delicate control on the component of perovskite, it is indispensable to know how different spacer cations affect their intrinsic properties. Here, we synthesized a series of quasi-2D perovskite single crystals with different organic spacer cations and conducted a systematic investigation to correlate the optoelectronic behaviors to the spacer cations. We revealed the coupling effect between the π-electron (PEA + ) and p orbital of I − from the inorganic framework, which changed the electronic configuration of resultant crystals leading to different band gap and carrier behavior. In particular, the anisotropic carrier mobility was probed quantitatively by space-charge limited current (SCLC) measurement, where PEA 2 MA 2 Pb 3 I 10 exhibited the highest in-plane mobility due to the reduced exciton binding energy and the lowest out-of-plane mobility because of the widest organic barrier.