Combinatorial tuning of electronic structure and thermoelectric properties in Co${}_2$MnAl${}_{1-x}$Si${}_x$ Weyl semimetals

Abstract

A tuning of Fermi level (E${}_F$) near Weyl points is one of the promising approaches to realize large anomalous Nernst effect (ANE). In this work, we introduce an efficient approach to tune E${}_F$ for the Co${}_2$MnAl Weyl semimetal through a layer-by-layer combinatorial deposition of Co${}_2$MnAl${}_{1-x}$Si${}_x$ (CMAS) thin film. A single-crystalline composition-spread film with x varied from 0 to 1 was fabricated. The structural characterization reveals the formation of single-phase CMAS alloy throughout the composition range with a gradual improvement of L2${}_1$ order with x similar to the co-sputtered single layered film, which validates the present fabrication technique. Hard X-ray photoemission spectroscopy for the CMAS composition-spread film directly confirmed the rigid band-like E${}_F$ shift of approximately 0.40 eV towards the composition gradient direction from x = 0 to 1. The anomalous Ettingshausen effect (AEE), the reciprocal of ANE, has been measured for whole x range using a single strip along the composition gradient using the lock-in thermography technique. The similarity of the x dependence of observed AEE and ANE signals clearly demonstrates that the AEE measurement on the composition spread film is an effective approach to investigate the composition dependence of ANE of Weyl semimetal thin films and realize the highest performance without fabricating several films, which will accelerate the research for ANE-based energy harvesting

arXiv commenttotal 29 pages, 6 main figures, 3 supplementary figures, 1 supplementary table

References in corpus (24)

• Berry Phase Effects on Electronic Properties
• Large anomalous Nernst effect at room temperature in a chiral antiferromagnet
• Evidence for Magnetic Weyl Fermions in a Correlated Metal
• Universal Scaling Behavior of Anomalous Hall Effect and Anomalous Nernst Effect in Itinerant Ferromagnets
• Giant anomalous Nernst effect and quantum-critical scaling in a ferromagnetic semimetal
• Anomalous Nernst effect beyond the magnetization scaling relation in the ferromagnetic Heusler compound Co${}_2$MnGa
• Anomalous Nernst and Righi-Leduc effects in Mn${}_3$Sn: Berry curvature and entropy flow
• Properties of the quaternary half-metal-type Heusler alloy Co${}_2$Mn${}_{1-x}$Fe${}_x$Si
• Topological Hopf and chain link semimetal states and their application to Co2MnGa (Theory and Materials Prediction)
• Nernst and magneto-thermal conductivity in a lattice model of Weyl fermions
• Thermal imaging of spin Peltier effect
• Analysis of L21-ordering in full-Heusler Co2FeSi alloy thin films formed by rapid thermal annealing
• Large anomalous Nernst effect in thin films of the Weyl semimetal Co2MnGa
• Proximity-free enhancement of anomalous Nernst effects in metallic multilayers
• Fermi level tuning and atomic ordering induced giant anomalous Nernst effect in Co2MnAl1-xSix Heusler alloy
• Spin-polarized Weyl cones and gigantic anomalous Nernst effect in ferromagnetic Heusler films
• Heat flux sensing by anomalous Nernst effect in Fe-Al thin films on a flexible substrate
• Observation of anomalous Ettingshausen effect and large transverse thermoelectric conductivity in permanent magnets
• Visualization of Anomalous Ettingshausen Effect in a Ferromagnetic Film: Direct Evidence of Different Symmetry from Spin Peltier Effect
• Scalable Nernst Thermoelectric Power using a Coiled Galfenol Wire
• Thermographic measurements of the spin Peltier effect in metal/yttrium-iron-garnet junction systems
• Large Anomalous Nernst Effect in a Skyrmion Crystal
• High energy, high resolution photoelectron spectroscopy of Co2Mn(1-x)Fe(x)Si
• Spin-mediated charge-to-heat current conversion phenomena in ferromagnetic binary alloys

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