Search

A correction is presented to the article "Controllable Synthesis of Submillimeter Single-Crystal Monolayer Graphene Domains on Copper Foils by Suppressing Nucleation," published in a 2012 issue by Hong Wang, Guanzhong Wang, Pengfei Bao, Shaolin Yang, Wei Zhu, Xing Xie, and Wen-Jun Zhang.

In a step towards topological quantum computation, a quantized Majorana conductance has been demonstrated for a semiconducting nanowire coupled to a superconductor. Majorana modes braced for braiding A semiconducting nanowire coupled to a superconductor can be tuned to topological superconducting states, which are thought to host localized quasiparticles called Majorana zero-modes at the ends of the wire. Such modes obey non-Abelian statistics, and braiding them could lead to a new type of computing known as topological quantum computation. Their name comes from the connection to Majorana fermions, which are their own antiparticle. This particle-antiparticle symmetry should make Majorana zero-modes detectable through differential conductance experiments, as a peak at zero-bias should emerge that is quantized at the universal conductance value of 2e.sup.2/h. Previous experiments have shown interesting features in such zero-bias peaks, but quantized conductance has remained elusive. Leo Kouwenhoven and colleagues now demonstrate a quantized Majorana conductance that is robust against electric and magnetic fields. This is an important step towards braiding experiments. Majorana zero-modes--a type of localized quasiparticle--hold great promise for topological quantum computing.sup.1. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance.sup.2. The height of the Majorana zero-bias peak is predicted to be quantized at the universal conductance value of 2e.sup.2/h at zero temperature.sup.3 (where e is the charge of an electron and h is the Planck constant), as a direct consequence of the famous Majorana symmetry in which a particle is its own antiparticle. The Majorana symmetry protects the quantization against disorder, interactions and variations in the tunnel coupling.sup.3,4,5. Previous experiments.sup.6, however, have mostly shown zero-bias peaks much smaller than 2e.sup.2/h, with a recent observation.sup.7 of a peak height close to 2e.sup.2/h. Here we report a quantized conductance plateau at 2e.sup.2/h in the zero-bias conductance measured in indium antimonide semiconductor nanowires covered with an aluminium superconducting shell. The height of our zero-bias peak remains constant despite changing parameters such as the magnetic field and tunnel coupling, indicating that it is a quantized conductance plateau. We distinguish this quantized Majorana peak from possible non-Majorana origins by investigating its robustness to electric and magnetic fields as well as its temperature dependence. The observation of a quantized conductance plateau strongly supports the existence of Majorana zero-modes in the system, consequently paving the way for future braiding experiments that could lead to topological quantum computing., Author(s): Hao Zhang [sup.1] , Chun-Xiao Liu [sup.2] , Sasa Gazibegovic [sup.3] , Di Xu [sup.1] , John A. Logan [sup.4] , Guanzhong Wang [sup.1] , Nick van Loo [sup.1] [...]

We presented a high-sensitivity temperature detection using an implanted single nitrogen-vacancy (NV) center array in diamond. The high-order thermal Carr-Purcell-Meiboom-Gill (TCPMG) method was performed on the implanted single NV center in diamond in a static magnetic field. We demonstrated that under small detunings for the two driving microwave frequencies, the oscillation frequency of the induced fluorescence of the NV center equals approximately the average of the detunings of the two driving fields. On the basis of the conclusion, the zero-field splitting D for the NV center and the corresponding temperature could be determined. The experiment showed that the coherence time for the high-order TCPMG was effectively extended, particularly up to 108 μs for TCPMG-8, about 14 times the value 7.7 μs for thermal Ramsey method. This coherence time corresponded to a thermal sensitivity of 10.1 mK/Hz1/2. We also detected the temperature distribution on the surface of a diamond chip in three different circumstances by using the implanted NV center array with the TCPMG-3 method. The experiment implies the feasibility of using implanted NV centers in high-quality diamonds to detect temperatures in biology, chemistry, materials science, and microelectronic systems with high sensitivity and nanoscale resolution. [ABSTRACT FROM AUTHOR]

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1038/s41586-021-03373-x., Author(s): Hao Zhang [sup.1] , Chun-Xiao Liu [sup.2] , Sasa Gazibegovic [sup.3] , Di Xu [sup.1] , John A. Logan [sup.4] , Guanzhong Wang [sup.1] , Nick van Loo [sup.1] [...]

Author(s): Hao Zhang [sup.1], Chun-Xiao Liu [sup.2], Sasa Gazibegovic [sup.3], Di Xu [sup.1], John A. Logan [sup.4], Guanzhong Wang [sup.1], Nick van Loo [sup.1], Jouri D. S. Bommer [sup.1], Michiel [...]

Byline: Qingtao Wang, Guanzhong Wang, Xiaoping Wang One-step low-temperature electrodeposition has been employed to fabricate ordered polycrystalline CdO nanowire arrays using anodic alumina membrane (AAM) templates by reduction of dissolved oxygen in presence of Cd2+ in the electrolyte. The CdO nanowires are uniform, and their length depends on the electrodeposition time and more than 30 [acute accent]m length nanowires can be easily got by this method. The structure characterisation and optical properties of the CdO nanowires are discussed in the paper. The blue shift of the direct band gap determined by the optical absorption of the CdO nanowires is attributed to the interface effect and the quantum confinement effect of the CdO nano-crystalline grains.

By efficient nanoscale plasma etching, the nitrogen-vacancy (NV) centers in diamond were brought to the sample surface step by step successfully. At each depth, we measured the ratios of spin coherence times before and after applying external spins on the surface, which reflected the contribution of external spins to the decoherence, and then investigated the relationships between depth and ratios. The values of ratios declined and then rose with the decreasing depth, which was attributed to the decoherence influenced by external spins, surface spins, discrete surface spin effects, and electric field noise. Moreover, our work experimentally and theoretically revealed a characteristic depth at which the NV center would experience relatively the strongest decoherence caused by external spins in consideration of inevitable surface spins. And the characteristic depth was found depending on the local environments of NV centers and the density of surface spins. [ABSTRACT FROM AUTHOR]