Field-Induced Metal–Insulator Transition inβ-EuP3

Metal–insulator transition(MIT)is one of the most conspicuous phenomena in correlated electron systems.However such a transition has rarely been induced by an external magnetic field as the field scale is normally too small compared with the charge gap.We present the observation of a magnetic-field-driven MIT in a magnetic semiconductorβ-EuP 3.Concomitantly,we find a colossal magnetoresistance in an extreme way:the resistance drops billionfold at 2 K in a magnetic field less than 3 T.We ascribe this striking MIT as a field-driven transition from an antiferromagnetic and paramagnetic insulator to a spin-polarized topological semimetal,in which the spin configuration of Eu 2+cations and spin-orbital coupling play a crucial role.As a phosphorene-bearing compound whose electrical properties can be controlled by the application of field,β-EuP 3 may serve as a tantalizing material in the basic research and even future electronics.

Efficiently adding mode multiplexing for cost-effective,high-capacity fiber links

For decades,a powerful approach to adding data capacity in an optical communication link has been to multiplex independent data-carrying channels and transmit them simultaneously along a fiber.^(1)For example,wavelength-division-multiplexing(WDM)was a key technology in the 1990s and early 2000s to dramatically increase aggregate capacity in a fiber by multiplexing beams of different wavelengths.^(2)For the past roughly 15 years,there has been great promise that space-division-multiplexing(SDM)may bring similar capacity enhancements to optical fiber communications.^(1–3)

Investigation of point-contact Andreev reflection on magnetic Weyl semimetal Co3Sn2S2

Magnetic Weyl semimetals(WSMs)with broken time-reversal symmetry(TRS)hosting topological band structures are expected to provide an ideal platform for investigating topological superconductivity and spintronics.However,the experimental verification of magnetic WSMs is very challenging.Very recently,the kagome magnet Co3Sn2S2 was confirmed to be a magnetic WSM by both angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy and consequently has become the focus of great attention.This paper reports a point-contact Andreev-reflection spectroscopy(PCARS)investigation on the(001)surface and the side surface of the Co3Sn2S2 single crystals,respectively.The measurements from the sample’s(001)and side surfaces provide experimental evidence for transport spin polarization in the Co3Sn2S2 magnetic WSM.Furthermore,the superconducting proximity effect in the Co3Sn2S2 single crystal is successfully detected.The point-contact spectra(PCS)along the in-plane direction cannot be well fitted by theoretical models based on s-wave pairing,indicating that possible triplet p-wave superconductivity may be triggered at the interface,which paves the way for the future exploration of the topological superconductivity and Majorana states in broken TRS WSMs.