Spin-polarized Weyl cones and gigantic anomalous Nernst effect in ferromagnetic Heusler films

Abstract

Weyl semimetals are characterized by the presence of massless band dispersion in momentum space. When a Weyl semimetal meets magnetism, large anomalous transport properties emerge as a consequence of its topological nature. Here, using $in-situ$ spin- and angle-resolved photoelectron spectroscopy combined with $abinitio$ calculations, we visualize the spin-polarized Weyl cone and flat-band surface states of ferromagnetic Co${}_2$MnGa films with full remanent magnetization. We demonstrate that the anomalous Hall and Nernst conductivities systematically grow when the magnetization-induced massive Weyl cone at a Lifshitz quantum critical point approaches the Fermi energy, until a high anomalous Nernst thermopower of $\sim 6.2$ $\mu \mathrm{V}{\mathrm{K}}^{-1}$ is realized at room temperature. Given this topological quantum state and full remanent magnetization, Co${}_2$MnGa films are promising for realizing high efficiency heat flux and magnetic field sensing devices operable at room temperature and zero-field.

arXiv comment25 pages, 5 figures, 1 table

References in corpus (30)

• Berry Phase Effects on Electronic Properties
• Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
• Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
• Type-II Weyl Semimetals
• Topological Materials: Weyl Semimetals
• Giant anomalous Hall effect in a ferromagnetic Kagome-lattice semimetal
• Observation of Weyl nodes in TaAs
• First Principles Calculation of Anomalous Hall Conductivity in Ferromagnetic bcc Fe
• Magnetic Weyl Semimetal Phase in a Kagome Crystal
• Large anomalous Nernst effect at room temperature in a chiral antiferromagnet
• Large intrinsic anomalous Hall effect in half-metallic ferromagnet Co3Sn2S2 with magnetic Weyl fermions
• Evidence for Magnetic Weyl Fermions in a Correlated Metal
• Berry phase effect in anomalous thermoelectric transport
• Giant anomalous Nernst effect and quantum-critical scaling in a ferromagnetic semimetal
• Discovery of topological Weyl fermion lines and drumhead surface states in a room temperature magnet
• Time-Reversal-Breaking Weyl Fermions in Magnetic Heusler Alloys
• Zero-field Nernst effect in a ferromagnetic kagome-lattice Weyl-semimetal Co3Sn2S2
• Anomalous Nernst effect beyond the magnetization scaling relation in the ferromagnetic Heusler compound Co${}_2$MnGa
• Topological Hopf and chain link semimetal states and their application to Co2MnGa (Theory and Materials Prediction)
• Discovery of a new type of topological Weyl fermion semimetal state in Mo${}_x$W${}_{1-x}$Te${}_2$
• Large anomalous Nernst effect in thin films of the Weyl semimetal Co2MnGa
• Fermi level tuning and atomic ordering induced giant anomalous Nernst effect in Co2MnAl1-xSix Heusler alloy
• Anomalous transverse response of Co${}_2$MnGa and universality of the room-temperature ${\alpha }_{ij}^A/{\sigma }_{ij}^A$ ratio across topological magnets
• Heat flux sensing by anomalous Nernst effect in Fe-Al thin films on a flexible substrate
• Large anomalous Hall and Nernst effect from nodal line symmetry breaking in Fe${}_2$MnX (X=P,As,Sb)
• Thickness dependence of the anomalous Nernst effect and the Mott relation of Weyl-semimetal Co2MnGa thin films
• Characterization of topological band structures away from the Fermi level by anomalous Nernst measurements
• Surface spin polarization of the non-stoichiometric Heusler compound Co2Mn(alpha)Si
• Monitoring surface resonances on Co2MnSi(100) by spin-resolved photoelectron spectroscopy
• Linear Response in Topological Materials

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• Logarithmic Criticality in Transverse Thermoelectric Conductivity of the Ferromagnetic Topological Semimetal CoMnSb
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