Frontiers in Electronic Materials最新文献

{"title":"Effects of the Order Parameter Anisotropy on the Vortex Lattice in UPt3","authors":"K. Avers, W. Gannon, A. Leishman, L. Debeer-Schmitt, W. Halperin, M. Eskildsen","doi":"10.3389/femat.2022.878308","DOIUrl":"https://doi.org/10.3389/femat.2022.878308","url":null,"abstract":"We have used small-angle neutron scattering to determine the vortex lattice phase diagram in the topological superconductor UPt3 for the applied magnetic field along the crystalline c-axis. A triangular vortex lattice is observed throughout the superconducting state, but with an orientation relative to the hexagonal basal plane that changes with field and temperature. At low temperature, in the chiral B phase, the vortex lattice undergoes a non-monotonic rotation with increasing magnetic field. The rotation amplitude decreases with increasing temperature and vanishes before reaching the A phase. Within the A phase an abrupt ±15° vortex lattice rotation was previously reported by Huxley et al., Nature 406, 160-164 (2000). The complex phase diagram may be understood from competing effects of the superconducting order parameter, the symmetry breaking field, and the Fermi surface anisotropy. The low-temperature rotated phase, centered around 0.8 T, reported by Avers et al., Nature Physics 16, 531-535 (2020), can be attributed directly to the symmetry breaking field.","PeriodicalId":119676,"journal":{"name":"Frontiers in Electronic Materials","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125859912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermoelectric Materials: Current Status and Future Challenges","authors":"Peter A. Finn, Ceyla Asker, K. Wan, E. Bilotti, O. Fenwick, C. Nielsen","doi":"10.3389/femat.2021.677845","DOIUrl":"https://doi.org/10.3389/femat.2021.677845","url":null,"abstract":"Net zero refers to the balance of the amount of greenhouse gas emissions produced and the amount removed from the atmosphere, and many companies and states have committed themselves to net zero targets. In June 2019, the United Kingdom became the first major economy in the world to pass a net zero emissions law. This ambitious target aims to reduce the UK’s net emissions of greenhouse gases by 100 per cent relative to 1,990 levels by 2,050 and replaces the UK’s previous target to reduce emissions by at least 80%. Sweden, France, Denmark, New Zealand and Hungary have also now succeeded in putting net zero targets into law (Net Zero Emissions Race, 2020). Progress towards these net zero goals has so far been slow. For example, the United Kingdom is behind on even the original 80% target, and achieving the current aim by 2,050 will be challenging. One thing that is clear to the scientific community is that improvements in technology between now and 2,050 will be key to bring the net zero target within reach. However, this will only happen if we can identify technologies for accelerated development and invest in them now, so we can deliver benefits before the 2,050 deadline. There are multiple areas where new technologies can assist in energy generation and storage, including photovoltaics, wind and water turbines, the hydrogen economy, caloric materials and batteries, as well as energy saving technologies such as low loss electronics. Thermoelectric energy conversion materials were identified by the Henry Royce Institute and the Institute of Physics as a key area of materials research for achieving net zero emissions in the Materials for the Energy Transition (2019) report. Space heating and cooling (e.g., central heating or air conditioning), is one of the main contributors to emissions and accounts for around 17% of the UK’s CO2 emissions (Department for Business, Energy and industrial Strategy, 2018). In Saudi Arabia, one of the hottest and driest countries in the world, more than 70% of the kingdom’s electricity produced per year is consumed purely for air conditioning and cooling purposes, with the demand doubling during the summer (Demirbas et al., 2017). This home water and space heating is typically achieved through burning natural gas in countries with access to natural gas, and through electrically-powered airsource heat pumps elsewhere. More widespread deployment of air-source heat pumps creates increased electricity demand, so solar-integrated heat pumps are also being investigated as another potential alternative to meet current space heating and domestic hot water demands with a reduced draw from the grid. However, these pumps use refrigerants such as HFCs, which are powerful greenhouse gases, so heat pumps that use other types of materials, such as thermoelectric and caloric materials need to be investigated as “greener” options. Thermoelectric materials use temperature differences to generate electrical energy. They can therefore pro","PeriodicalId":119676,"journal":{"name":"Frontiers in Electronic Materials","volume":"208 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114254048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hot Hydride Superconductivity Above 550 K","authors":"A. Grockowiak, M. Ahart, T. Helm, G. Garbarino, K. Glazyrin, W. Coniglio, Ravhi S Kumar, M. Somayazulu, Y. Meng, Morgan Oliff, V. Williams, N. Ashcroft, R. Hemley, S. Tozer","doi":"10.3389/femat.2022.837651","DOIUrl":"https://doi.org/10.3389/femat.2022.837651","url":null,"abstract":"The search for room temperature superconductivity has accelerated in the last few years driven by experimentally accessible theoretical predictions that indicated alloying dense hydrogen with other elements could produce conventional superconductivity at high temperatures and pressures. These predictions helped inform the synthesis of simple binary hydrides that culminated in the discovery of the superhydride LaH10 with a superconducting transition temperature T c of 260 K at 180 GPa. We have now successfully synthesized a metallic La-based superhydride with an initial T c of 294 K. When subjected to subsequent thermal excursions that promoted a chemical reaction to a higher order system, the T c onset was driven irreversibly to 556 K. X-ray characterization confirmed the formation of a distorted LaH10 based backbone that suggests the formation of ternary or quaternary compounds with substitution at the La and/or H sites. The results provide evidence for hot superconductivity, aligning with recent predictions for higher order hydrides under pressure.","PeriodicalId":119676,"journal":{"name":"Frontiers in Electronic Materials","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115506533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}