We propose a different entanglement concentration protocol （ECP） for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional el...We propose a different entanglement concentration protocol （ECP） for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional electron. For each nonlocal N-electron system, Alice first entangles it with the additional electron, and then she projects the additional electron onto an orthogonal basis for dividing the N-electron systems into two groups. In the first group, the N parties obtain a subset of N-electron systems in a maximally entangled state directly. In the second group, they obtain some less-entangled N-electron systems, which are the resource for the entanglement concentration in the next round. By iterating the entanglement concentration process several times, the present ECP has the maximal success probability, which is the theoretical limit of an ECP, equal to the entanglement of the partially entangled state, and higher than the others. This ECP may be useful in quantum computers based on electron-spin systems in the future.展开更多
Combining theory and computation,we explore the Goos–H¨anchen(GH)effect for electrons in a single-layered semiconductor microstructure(SLSM)modulated by Dresselhaus spin–orbit coupling(SOC).GH displacement depe...Combining theory and computation,we explore the Goos–H¨anchen(GH)effect for electrons in a single-layered semiconductor microstructure(SLSM)modulated by Dresselhaus spin–orbit coupling(SOC).GH displacement depends on electron spins thanks to Dresselhaus SOC,therefore electron spins can be separated from the space domain and spinpolarized electrons in semiconductors can be realized.Both the magnitude and sign of the spin polarization ratio change with the electron energy,in-plane wave vector,strain engineering and semiconductor layer thickness.The spin polarization ratio approaches a maximum at resonance;however,no electron-spin polarization occurs in the SLSM for a zero in-plane wave vector.More importantly,the spin polarization ratio can be manipulated by strain engineering or semiconductor layer thickness,giving rise to a controllable spatial electron-spin splitter in the field of semiconductor spintronics.展开更多
钙钛矿氧化物异质界面中二维电子气(two-dimensional electron gas,2DEG)与界面超导性的发现使其成为研究热点之一.近年来,氧化物界面研究取得突破性进展,除了传统的LaAlO_(3)/SrTiO_(3)(LAO/STO)界面,2021年在KTaO_(3)(KTO)界面也发现...钙钛矿氧化物异质界面中二维电子气(two-dimensional electron gas,2DEG)与界面超导性的发现使其成为研究热点之一.近年来,氧化物界面研究取得突破性进展,除了传统的LaAlO_(3)/SrTiO_(3)(LAO/STO)界面,2021年在KTaO_(3)(KTO)界面也发现超导性,其超导转变温度(Tc)较LAO/STO高出一个数量级,约为2 K,引起广泛关注.与STO界面体系相比,KTO氧化物界面显现出高载流子迁移率、强自旋轨道耦合(spin-orbit coupling,SOC)等特点,为理解非常规超导机制和构建新物理特性的研究提供了新途径,使KTO异质界面成为未来电子和自旋电子应用的有力候选者.本文旨在总结近5年KTO界面的最新进展,概述多种氧化物与KTO界面超导的新奇物理现象,并讨论目前研究中尚未解决的问题,为未来研究提供参考.展开更多
The microemulsion method for preparing ZnO nanocrystallites was reported.Through measuring ZnO microcrystllite ESR spectra, we found that at room temperature it has a significant ESR signal and its intensity descends ...The microemulsion method for preparing ZnO nanocrystallites was reported.Through measuring ZnO microcrystllite ESR spectra, we found that at room temperature it has a significant ESR signal and its intensity descends with the increase of annealed temperature. This result is in contrast with that of bulk ZnO which is a diamagnetic material and no ESR signal. Finally it was found and verified that on the surfaces of ZnO nanocrystallites there are a lot of oxygen vacancies and defects which trap electrons and form paramagnetic centers to provide the observed ESR signal.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10974020 and 11174039)the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-11-0031)the Fundamental Research Funds for the Central Universities, China
文摘We propose a different entanglement concentration protocol （ECP） for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional electron. For each nonlocal N-electron system, Alice first entangles it with the additional electron, and then she projects the additional electron onto an orthogonal basis for dividing the N-electron systems into two groups. In the first group, the N parties obtain a subset of N-electron systems in a maximally entangled state directly. In the second group, they obtain some less-entangled N-electron systems, which are the resource for the entanglement concentration in the next round. By iterating the entanglement concentration process several times, the present ECP has the maximal success probability, which is the theoretical limit of an ECP, equal to the entanglement of the partially entangled state, and higher than the others. This ECP may be useful in quantum computers based on electron-spin systems in the future.
基金Project supported by the National Natural Science Foundation of China(Grant No.62164005).
文摘Combining theory and computation,we explore the Goos–H¨anchen(GH)effect for electrons in a single-layered semiconductor microstructure(SLSM)modulated by Dresselhaus spin–orbit coupling(SOC).GH displacement depends on electron spins thanks to Dresselhaus SOC,therefore electron spins can be separated from the space domain and spinpolarized electrons in semiconductors can be realized.Both the magnitude and sign of the spin polarization ratio change with the electron energy,in-plane wave vector,strain engineering and semiconductor layer thickness.The spin polarization ratio approaches a maximum at resonance;however,no electron-spin polarization occurs in the SLSM for a zero in-plane wave vector.More importantly,the spin polarization ratio can be manipulated by strain engineering or semiconductor layer thickness,giving rise to a controllable spatial electron-spin splitter in the field of semiconductor spintronics.
文摘钙钛矿氧化物异质界面中二维电子气(two-dimensional electron gas,2DEG)与界面超导性的发现使其成为研究热点之一.近年来,氧化物界面研究取得突破性进展,除了传统的LaAlO_(3)/SrTiO_(3)(LAO/STO)界面,2021年在KTaO_(3)(KTO)界面也发现超导性,其超导转变温度(Tc)较LAO/STO高出一个数量级,约为2 K,引起广泛关注.与STO界面体系相比,KTO氧化物界面显现出高载流子迁移率、强自旋轨道耦合(spin-orbit coupling,SOC)等特点,为理解非常规超导机制和构建新物理特性的研究提供了新途径,使KTO异质界面成为未来电子和自旋电子应用的有力候选者.本文旨在总结近5年KTO界面的最新进展,概述多种氧化物与KTO界面超导的新奇物理现象,并讨论目前研究中尚未解决的问题,为未来研究提供参考.
文摘The microemulsion method for preparing ZnO nanocrystallites was reported.Through measuring ZnO microcrystllite ESR spectra, we found that at room temperature it has a significant ESR signal and its intensity descends with the increase of annealed temperature. This result is in contrast with that of bulk ZnO which is a diamagnetic material and no ESR signal. Finally it was found and verified that on the surfaces of ZnO nanocrystallites there are a lot of oxygen vacancies and defects which trap electrons and form paramagnetic centers to provide the observed ESR signal.
