We demonstrate integrated photonic circuits for quantum devices using sputtered polycrystalline aluminum nitride(Al N)on insulator.On-chip Al N waveguide directional couplers,which are one of the most important compon...We demonstrate integrated photonic circuits for quantum devices using sputtered polycrystalline aluminum nitride(Al N)on insulator.On-chip Al N waveguide directional couplers,which are one of the most important components in quantum photonics,are fabricated and show the output power splitting ratios from 50:50 to 99:1.Polarization beam splitters with an extinction ratio of more than 10 d B are also realized from the Al N directional couplers.Using the fabricated Al N waveguide beam splitters,we observe Hong–Ou–Mandel interference with a visibility of 91.7%±5.66%.展开更多
We present a new class of metastable high-entropy alloys(HEAs),triggering deformation-induced martensitic transformation(DIMT)from face-centered-cubic(FCC)to body-centered-cubic(BCC),i.e.,BCC-DIMT.Through the ab-initi...We present a new class of metastable high-entropy alloys(HEAs),triggering deformation-induced martensitic transformation(DIMT)from face-centered-cubic(FCC)to body-centered-cubic(BCC),i.e.,BCC-DIMT.Through the ab-initio calculation based on 1 st order axial interaction model and combined with the Gibbs free energy calculation,the addition of Si is considered as a critical element which enables to reduce the intrinsic stacking fault energy(ISFE)in Si_xV_((9-x))Cr_(10)Mn_5 Fe_(46)Co_(30)(x=2,4,and 7 at.%)alloy system.The ISFE decreases from-30.4 to-35.5 mJ/m^(2)as the Si content increases from 2 to 7 at.%,which well corresponds to the reduced phase stability of FCC against HCP.The BCC-DIMT occurs in all the alloys via intermediate HCP martensite,and the HCP martensite provides nucleation sites of BCC martensite.Therefore,the transformation rate enhances as the Si content increases in an earlier deformation ra nge.However,the BCC-DIMT is also affected by the phase stability of FCC against BCC,and the stability is the highest at the Si content of 7 at.%.Thus,the 7Si alloy presents the moderate transformation rate in the later deformation range.Due to the well-controlled transformation rate and consequent strain-ha rdening rate,the 7Si alloy possesses the superior combination of strength and ductility beyond 1 GPa of tensile strength at room temperature.Our results suggest that the Si addition can be a favorable candidate in various metastable HEAs for the further property improvement.展开更多
基金Korea Institute of Science and Technology (2E32241,2E32801)National Research Council of Science and Technology (CAP21031-200)+1 种基金Institute for Information and Communications Technology Promotion (2020-0-00947,2020-0-00972)National Research Foundation of Korea (2019M3E4A1079777,2021M1A2A2043892).
文摘We demonstrate integrated photonic circuits for quantum devices using sputtered polycrystalline aluminum nitride(Al N)on insulator.On-chip Al N waveguide directional couplers,which are one of the most important components in quantum photonics,are fabricated and show the output power splitting ratios from 50:50 to 99:1.Polarization beam splitters with an extinction ratio of more than 10 d B are also realized from the Al N directional couplers.Using the fabricated Al N waveguide beam splitters,we observe Hong–Ou–Mandel interference with a visibility of 91.7%±5.66%.
基金the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003)the Fundamental Research Funds for the Central Universities(2020CDJQY-A028 and 2020CDJ-LHZZ-074)the Natural Science Foundation of Chongqing(cstc2020jcyj-msxmX0629)。
基金the Korea University Grant for the eightth authorCreative Materials Discovery Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(NRF-2016M3D1A1023383)+1 种基金the Brain Korea 21 PLUS Project for Center for Creative Industrial MaterialsKorea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(P0002019,The Competency Development Program for Industry Specialist)。
文摘We present a new class of metastable high-entropy alloys(HEAs),triggering deformation-induced martensitic transformation(DIMT)from face-centered-cubic(FCC)to body-centered-cubic(BCC),i.e.,BCC-DIMT.Through the ab-initio calculation based on 1 st order axial interaction model and combined with the Gibbs free energy calculation,the addition of Si is considered as a critical element which enables to reduce the intrinsic stacking fault energy(ISFE)in Si_xV_((9-x))Cr_(10)Mn_5 Fe_(46)Co_(30)(x=2,4,and 7 at.%)alloy system.The ISFE decreases from-30.4 to-35.5 mJ/m^(2)as the Si content increases from 2 to 7 at.%,which well corresponds to the reduced phase stability of FCC against HCP.The BCC-DIMT occurs in all the alloys via intermediate HCP martensite,and the HCP martensite provides nucleation sites of BCC martensite.Therefore,the transformation rate enhances as the Si content increases in an earlier deformation ra nge.However,the BCC-DIMT is also affected by the phase stability of FCC against BCC,and the stability is the highest at the Si content of 7 at.%.Thus,the 7Si alloy presents the moderate transformation rate in the later deformation range.Due to the well-controlled transformation rate and consequent strain-ha rdening rate,the 7Si alloy possesses the superior combination of strength and ductility beyond 1 GPa of tensile strength at room temperature.Our results suggest that the Si addition can be a favorable candidate in various metastable HEAs for the further property improvement.
