Correcting the forecast bias of numerical weather prediction models is important for severe weather warnings.The refined grid forecast requires direct correction on gridded forecast products,as opposed to correcting f...Correcting the forecast bias of numerical weather prediction models is important for severe weather warnings.The refined grid forecast requires direct correction on gridded forecast products,as opposed to correcting forecast data only at individual weather stations.In this study,a deep learning method called CU-net is proposed to correct the gridded forecasts of four weather variables from the European Centre for Medium-Range Weather Forecast Integrated Forecasting System global model(ECMWF-IFS): 2-m temperature,2-m relative humidity,10-m wind speed,and 10-m wind direction,with a forecast lead time of 24 h to 240 h in North China.First,the forecast correction problem is transformed into an image-toimage translation problem in deep learning under the CU-net architecture,which is based on convolutional neural networks.Second,the ECMWF-IFS forecasts and ECMWF reanalysis data(ERA5) from 2005 to 2018 are used as training,validation,and testing datasets.The predictors and labels(ground truth) of the model are created using the ECMWF-IFS and ERA5,respectively.Finally,the correction performance of CU-net is compared with a conventional method,anomaly numerical correction with observations(ANO).Results show that forecasts from CU-net have lower root mean square error,bias,mean absolute error,and higher correlation coefficient than those from ANO for all forecast lead times from 24 h to 240 h.CU-net improves upon the ECMWF-IFS forecast for all four weather variables in terms of the above evaluation metrics,whereas ANO improves upon ECMWF-IFS performance only for 2-m temperature and relative humidity.For the correction of the 10-m wind direction forecast,which is often difficult to achieve,CU-net also improves the correction performance.展开更多
The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK...The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.展开更多
The facile reconfiguration of phases plays a pivotal role in enhancing the electrocatalytic production of H2 through heterostructure formation.While chemical methods have been explored extensively for this purpose,pla...The facile reconfiguration of phases plays a pivotal role in enhancing the electrocatalytic production of H2 through heterostructure formation.While chemical methods have been explored extensively for this purpose,plasma-based techniques offer a promising avenue for achieving heterostructured nano-frameworks.However,the conventional plasma approach introduces complexities,leading to a multi-step fabrication process and challenges in precisely controlling partial surface structure modulation due to the intricate interaction environment.In our pursuit of heterostructures with optimized oxygen evolution reaction(OER)behavior,we have designed a facile auxiliary insulator-confined plasma system to directly attain a Ni_(3)N-NiO heterostructure(hNiNO).By meticulously controlling the surface heating process during plasma processing,such approach allows for the streamlined fabrication of hNiNO nano-frameworks.The resulting nano-framework exhibits outstanding catalytic performance,as evidenced by its overpotential of 320 mV at a current density of 10 mA·cm^(-2),in an alkaline environment.This stands in stark contrast to the performance of NiO-covered Ni_(3)N fabricated using the conventional plasma method(sNiNO).Operando plasma diagnostics,coupled with numerical simulations,further substantiates the influence of surface heating due to auxiliary insulator confinement of the substrate on typical plasma parameters and the formation of the Ni_(3)N-NiO nanostructure,highlighting the pivotal role of controlled surface temperature in creating a high-performance heterostructured electrocatalyst.展开更多
Developing electrocatalysts with high activity and selectivity for the oxygen reduction reaction(ORR)is vital to promote the performance of the next-generation energy technologies,which depend on the efficiency of the...Developing electrocatalysts with high activity and selectivity for the oxygen reduction reaction(ORR)is vital to promote the performance of the next-generation energy technologies,which depend on the efficiency of the catalytic reduction of dioxygen.In the structure of cytochrome c oxidases(CcOs),a histidine imidazole residue binding to the axial position of Fe plays a crucial role in facilitating the selective reduction of O_(2)to water.Inspired by nature,we herein report on the synthesis of CoIII corrole 1 tethered with an imidazole ligand as well as its electrocatalytic ORR and O_(2)binding features.As compared to the imidazolium-free analogue,complex 1 displayed remarkably boosted activity for the selective four-electron/four-proton(4e-/4H+)ORR with a half-wave potential of E1/2=0.82 V versus reversible hydrogen electrode(RHE)in 0.1 mol/L KOH solutions.Importantly,we demonstrate that the tethered axial imidazole ligand improves the O_(2)binding ability of 1 thermodynamically and dynamically,which is crucial to boost electrocatalytic ORR performance.This work presents an example to improve electrocatalytic ORR activity and selectivity of Co corroles by introducing an axial imidazole ligand to enhance the O_(2)binding and activation.展开更多
Transition-metal based M-N_4/C catalysts are appealing for electrocatalytic oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). Employing model catalysts, which have well-defined molecular structures an...Transition-metal based M-N_4/C catalysts are appealing for electrocatalytic oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). Employing model catalysts, which have well-defined molecular structures and coordination environments, to investigate electrocatalytic performance of M-N_4/C sites for ORR and OER is of fundamental significance. Herein, we reported the use of Co tetra(phenyl)porphyrin 1 and Co tetra(pentafluorophenyl)porphyrin 2 as models to probe the role of Co-N_4/C sites for oxygen electrocatalysis. We showed that Co porphyrin 1 is more efficient than its structural analogue 2 for oxygen electrocatalysis in alkaline aqueous solutions, indicating that the electronrich Co-N_4/C site is more favored when noncovalently adsorbed on carbon supports. This work inspires rational design of reaction-oriented catalysts for sustainable energy storage and conversion technologies.展开更多
JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)...JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.展开更多
The Jiangmen Underground Neutrino Observatory(JUNO)features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector.Some of JUNO's features make it an excellent location for^8B solar neut...The Jiangmen Underground Neutrino Observatory(JUNO)features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector.Some of JUNO's features make it an excellent location for^8B solar neutrino measurements,such as its low-energy threshold,high energy resolution compared with water Cherenkov detectors,and much larger target mass compared with previous liquid scintillator detectors.In this paper,we present a comprehensive assessment of JUNO's potential for detecting^8B solar neutrinos via the neutrino-electron elastic scattering process.A reduced 2 MeV threshold for the recoil electron energy is found to be achievable,assuming that the intrinsic radioactive background^(238)U and^(232)Th in the liquid scintillator can be controlled to 10^(-17)g/g.With ten years of data acquisition,approximately 60,000 signal and 30,000 background events are expected.This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter,which will shed new light on the inconsistency between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework.IfDelta m^(2)_(21)=4.8times10^(-5);(7.5times10^(-5))eV^(2),JUNO can provide evidence of neutrino oscillation in the Earth at approximately the 3sigma(2sigma)level by measuring the non-zero signal rate variation with respect to the solar zenith angle.Moreover,JUNO can simultaneously measureDelta m^2_(21)using^8B solar neutrinos to a precision of 20% or better,depending on the central value,and to sub-percent precision using reactor antineutrinos.A comparison of these two measurements from the same detector will help understand the current mild inconsistency between the value of Delta m^2_(21)reported by solar neutrino experiments and the KamLAND experiment.展开更多
The wide-bandgap cubic-structure semiconductor In_(4)SnSe_(4) can be regarded as a product of compositing two typical layered thermoelectric materials SnSe and In_(4)Se_(3).Remarkably,In_(4)SnSe_(4) inherited low ther...The wide-bandgap cubic-structure semiconductor In_(4)SnSe_(4) can be regarded as a product of compositing two typical layered thermoelectric materials SnSe and In_(4)Se_(3).Remarkably,In_(4)SnSe_(4) inherited low thermal conductivity from its parent materials.To advance the potential thermoelectric property of In_(4)SnSe_(4),we systematically investigated its crystal structure and the origin of the intrinsic low thermal conductivity.In_(4)SnSe_(4) crystallized in a cubic phase(space group Pa3),with the lattice parameters of a=b=c=12.66Å.The anisotropy of IneSe bonds in the lattice determined the complex structure of In_(4)SnSe_(4) with 72 atoms in the primitive cell.More importantly,sound velocity and elastic properties unclosed the strong anharmonicity in In_(4)SnSe_(4),which contributed greatly to the low thermal conductivity.With first-principles calculations,it was found that the lone-pair electrons from In^(+)mainly caused the anharmonicity in the lattice.Additionally,Br was proved to be an effective dopant for In_(4)SnSe_(4) to improve the electrical transport properties.This work indicated that the complex wide-bandgap semiconductor In_(4)SnSe_(4) with cubic phase and intrinsic low thermal conductivity was a new promising thermoelectric material with appropriate doping.展开更多
基金supported in part by the National Key R&D Program of China (Grant No.2018YFF0300102)the National Natural Science Foundation of China (Grant Nos.41875049 and 41575050)the Beijing Natural Science Foundation (Grant No.8212025)。
文摘Correcting the forecast bias of numerical weather prediction models is important for severe weather warnings.The refined grid forecast requires direct correction on gridded forecast products,as opposed to correcting forecast data only at individual weather stations.In this study,a deep learning method called CU-net is proposed to correct the gridded forecasts of four weather variables from the European Centre for Medium-Range Weather Forecast Integrated Forecasting System global model(ECMWF-IFS): 2-m temperature,2-m relative humidity,10-m wind speed,and 10-m wind direction,with a forecast lead time of 24 h to 240 h in North China.First,the forecast correction problem is transformed into an image-toimage translation problem in deep learning under the CU-net architecture,which is based on convolutional neural networks.Second,the ECMWF-IFS forecasts and ECMWF reanalysis data(ERA5) from 2005 to 2018 are used as training,validation,and testing datasets.The predictors and labels(ground truth) of the model are created using the ECMWF-IFS and ERA5,respectively.Finally,the correction performance of CU-net is compared with a conventional method,anomaly numerical correction with observations(ANO).Results show that forecasts from CU-net have lower root mean square error,bias,mean absolute error,and higher correlation coefficient than those from ANO for all forecast lead times from 24 h to 240 h.CU-net improves upon the ECMWF-IFS forecast for all four weather variables in terms of the above evaluation metrics,whereas ANO improves upon ECMWF-IFS performance only for 2-m temperature and relative humidity.For the correction of the 10-m wind direction forecast,which is often difficult to achieve,CU-net also improves the correction performance.
基金supported by the Chinese Academy of Sciencesthe National Key R&D Program of China+22 种基金the CAS Center for Excellence in Particle PhysicsWuyi Universitythe Tsung-Dao Lee Institute of Shanghai Jiao Tong University in Chinathe Institut National de Physique Nucléaire et de Physique de Particules (IN2P3) in Francethe Istituto Nazionale di Fisica Nucleare (INFN) in Italythe Italian-Chinese collaborative research program MAECI-NSFCthe Fond de la Recherche Scientifique (F.R.S-FNRS)FWO under the "Excellence of Science-EOS" in Belgiumthe Conselho Nacional de Desenvolvimento Científico e Tecnològico in Brazilthe Agencia Nacional de Investigacion y Desarrollo in Chilethe Charles University Research Centrethe Ministry of Education,Youth,and Sports in Czech Republicthe Deutsche Forschungsgemeinschaft (DFG)the Helmholtz Associationthe Cluster of Excellence PRISMA+ in Germanythe Joint Institute of Nuclear Research (JINR)Lomonosov Moscow State University in Russiathe joint Russian Science Foundation (RSF)National Natural Science Foundation of China (NSFC) research programthe MOST and MOE in Taiwan,Chinathe Chulalongkorn UniversitySuranaree University of Technology in Thailandthe University of California at Irvine in USA
文摘The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.
基金supported by the National Natural Science Foundation of China(Nos.12304020,21905118,and 22378204)National Science Fund for Distinguished Young Scholars(No.T2125004)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20230909)Fundamental Research Funds for the Central Universities(No.30923011013)。
文摘The facile reconfiguration of phases plays a pivotal role in enhancing the electrocatalytic production of H2 through heterostructure formation.While chemical methods have been explored extensively for this purpose,plasma-based techniques offer a promising avenue for achieving heterostructured nano-frameworks.However,the conventional plasma approach introduces complexities,leading to a multi-step fabrication process and challenges in precisely controlling partial surface structure modulation due to the intricate interaction environment.In our pursuit of heterostructures with optimized oxygen evolution reaction(OER)behavior,we have designed a facile auxiliary insulator-confined plasma system to directly attain a Ni_(3)N-NiO heterostructure(hNiNO).By meticulously controlling the surface heating process during plasma processing,such approach allows for the streamlined fabrication of hNiNO nano-frameworks.The resulting nano-framework exhibits outstanding catalytic performance,as evidenced by its overpotential of 320 mV at a current density of 10 mA·cm^(-2),in an alkaline environment.This stands in stark contrast to the performance of NiO-covered Ni_(3)N fabricated using the conventional plasma method(sNiNO).Operando plasma diagnostics,coupled with numerical simulations,further substantiates the influence of surface heating due to auxiliary insulator confinement of the substrate on typical plasma parameters and the formation of the Ni_(3)N-NiO nanostructure,highlighting the pivotal role of controlled surface temperature in creating a high-performance heterostructured electrocatalyst.
基金We are grateful for support from the National Natural Science Foundation of China(21902099,22171176 and 22105010)Key Research and Development Program of Shaanxi(2023-YBGY-296)+1 种基金Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University,Fundamental Research Funds for the Central Universities(GK202203002)Research Funds of Shaanxi Normal University.
文摘Developing electrocatalysts with high activity and selectivity for the oxygen reduction reaction(ORR)is vital to promote the performance of the next-generation energy technologies,which depend on the efficiency of the catalytic reduction of dioxygen.In the structure of cytochrome c oxidases(CcOs),a histidine imidazole residue binding to the axial position of Fe plays a crucial role in facilitating the selective reduction of O_(2)to water.Inspired by nature,we herein report on the synthesis of CoIII corrole 1 tethered with an imidazole ligand as well as its electrocatalytic ORR and O_(2)binding features.As compared to the imidazolium-free analogue,complex 1 displayed remarkably boosted activity for the selective four-electron/four-proton(4e-/4H+)ORR with a half-wave potential of E1/2=0.82 V versus reversible hydrogen electrode(RHE)in 0.1 mol/L KOH solutions.Importantly,we demonstrate that the tethered axial imidazole ligand improves the O_(2)binding ability of 1 thermodynamically and dynamically,which is crucial to boost electrocatalytic ORR performance.This work presents an example to improve electrocatalytic ORR activity and selectivity of Co corroles by introducing an axial imidazole ligand to enhance the O_(2)binding and activation.
基金supported by the "Thousand Talents Program" of China, the Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University, the National Natural Science Foundation of China (21573139, 21773146, 21902099, and 21905167)theChinaPostdoctoralScienceFoundation (2019M650232)+2 种基金the Fundamental Research Funds for the Central Universities (GK202003025)the Research Funds of Shaanxi Normal Universitythe Opening Fund of State Key Laboratory of Heavy Oil Processing。
文摘Transition-metal based M-N_4/C catalysts are appealing for electrocatalytic oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). Employing model catalysts, which have well-defined molecular structures and coordination environments, to investigate electrocatalytic performance of M-N_4/C sites for ORR and OER is of fundamental significance. Herein, we reported the use of Co tetra(phenyl)porphyrin 1 and Co tetra(pentafluorophenyl)porphyrin 2 as models to probe the role of Co-N_4/C sites for oxygen electrocatalysis. We showed that Co porphyrin 1 is more efficient than its structural analogue 2 for oxygen electrocatalysis in alkaline aqueous solutions, indicating that the electronrich Co-N_4/C site is more favored when noncovalently adsorbed on carbon supports. This work inspires rational design of reaction-oriented catalysts for sustainable energy storage and conversion technologies.
基金Supported by the Chinese Academy of Sciencesthe National Key R&D Program of China+18 种基金the CAS Center for Excellence in Particle Physics,Wuyi Universitythe Tsung-Dao Lee Institute of Shanghai Jiao Tong University in Chinathe Institut National de Physique Nucléaire et de Physique de Particules(IN2P3)in Francethe Istituto Nazionale di Fisica Nucleare(INFN)in Italythe Italian-Chinese collaborative research program MAECI-NSFCthe Fond de la Recherche Scientifique(F.R.S-FNRS)FWO under the“Excellence of Science-EOS in Belgium”the Conselho Nacional de Desenvolvimento Científico e Tecnològico in Brazilthe Agencia Nacional de Investigacion y Desarrollo and ANID-Millennium Science Initiative Program-ICN2019_044 in Chilethe Charles University Research Centre and the Ministry of Education,Youth,and Sports in Czech Republicthe Deutsche Forschungsgemeinschaft(DFG)the Helmholtz Associationthe Cluster of Excellence PRISMA+in Germanythe Joint Institute of Nuclear Research(JINR)and Lomonosov Moscow State University in Russiathe joint Russian Science Foundation(RSF)National Natural Science Foundation of China(NSFC)research programthe MOST and MOE in Taiwanthe Chulalongkorn University and Suranaree University of Technology in Thailand,University of California at Irvinethe National Science Foundation in USA。
文摘JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.
基金This work was supported by the Chinese Academy of Sciences,the National Key R&D Program of China,the CAS Center for Excellence in Particle Physics,the Joint Large Scale Scientific Facility Funds of the NSFC and CAS,Wuyi University,and the Tsung-Dao Lee Instiute of Shanghai Jiao Tong University in China,the In stiut National de Physique Nucleaire et de Physique de Particules(IN2P3)in France,the Istituto Nazionale di Fisica Nucleare(INFN)in Italy,the Fond de la Recherche Scintifique(F.R.S-FNRS)and FWO under the"Excellence of Science-EOS"in Belgium,the Conselho Nacional de Desenvolvimento Cientificoce Tecnologico in Brazil,the Agencia Nacional de Investigacion y Desrrollo in Chile,the Charles University Research Centre and the Ministry of Education,Youth,and Sports in Czech Republic,the Deutsche Forschungsgemeinschaft(DFG),the Helmholtz Association,and the Cluster of Exellence PRISMA+in Germany,the Joint Institute of Nuclear Research(JINR),Lomonosov Moscow State University,and Russian Foundation for Basic Research(RFBR)in Russia,the MOST and MOE in Taiwan,the Chu-lalongkorm University and Suranaree University of Technology in Thailand,and the University of aliformia at Irvine in USA.
文摘The Jiangmen Underground Neutrino Observatory(JUNO)features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector.Some of JUNO's features make it an excellent location for^8B solar neutrino measurements,such as its low-energy threshold,high energy resolution compared with water Cherenkov detectors,and much larger target mass compared with previous liquid scintillator detectors.In this paper,we present a comprehensive assessment of JUNO's potential for detecting^8B solar neutrinos via the neutrino-electron elastic scattering process.A reduced 2 MeV threshold for the recoil electron energy is found to be achievable,assuming that the intrinsic radioactive background^(238)U and^(232)Th in the liquid scintillator can be controlled to 10^(-17)g/g.With ten years of data acquisition,approximately 60,000 signal and 30,000 background events are expected.This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter,which will shed new light on the inconsistency between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework.IfDelta m^(2)_(21)=4.8times10^(-5);(7.5times10^(-5))eV^(2),JUNO can provide evidence of neutrino oscillation in the Earth at approximately the 3sigma(2sigma)level by measuring the non-zero signal rate variation with respect to the solar zenith angle.Moreover,JUNO can simultaneously measureDelta m^2_(21)using^8B solar neutrinos to a precision of 20% or better,depending on the central value,and to sub-percent precision using reactor antineutrinos.A comparison of these two measurements from the same detector will help understand the current mild inconsistency between the value of Delta m^2_(21)reported by solar neutrino experiments and the KamLAND experiment.
基金This work was supported by the National Natural Science Foundation of China(52002042)the National Key Research and Development Program of China(2018YFA0702100)+3 种基金National Postdoctoral Program for Innovative Talents(BX20200028)Foundation Key Scientific Research Project of Universities in Henan Province(19zx008)L.D.Z.thanks for the support from the National Science Fund for Distinguished Young Scholars(51925101)the high performance computing(HPC)resources at Beihang University。
文摘The wide-bandgap cubic-structure semiconductor In_(4)SnSe_(4) can be regarded as a product of compositing two typical layered thermoelectric materials SnSe and In_(4)Se_(3).Remarkably,In_(4)SnSe_(4) inherited low thermal conductivity from its parent materials.To advance the potential thermoelectric property of In_(4)SnSe_(4),we systematically investigated its crystal structure and the origin of the intrinsic low thermal conductivity.In_(4)SnSe_(4) crystallized in a cubic phase(space group Pa3),with the lattice parameters of a=b=c=12.66Å.The anisotropy of IneSe bonds in the lattice determined the complex structure of In_(4)SnSe_(4) with 72 atoms in the primitive cell.More importantly,sound velocity and elastic properties unclosed the strong anharmonicity in In_(4)SnSe_(4),which contributed greatly to the low thermal conductivity.With first-principles calculations,it was found that the lone-pair electrons from In^(+)mainly caused the anharmonicity in the lattice.Additionally,Br was proved to be an effective dopant for In_(4)SnSe_(4) to improve the electrical transport properties.This work indicated that the complex wide-bandgap semiconductor In_(4)SnSe_(4) with cubic phase and intrinsic low thermal conductivity was a new promising thermoelectric material with appropriate doping.
