Susumu Minami

• PhD
• Assistant Professor at Kyoto University

We elucidate the transport properties and electronic structures of distorted rutile-type WO2. Electrical resistivity and Hall effect measurements of high-quality single crystals revealed the transport property characteristics of topological materials; these characteristics included an extremely large magnetoresistance of 13 200% (2 K and 9 T) and a...

Realization of ultrasmall scale electromechanical materials has been promising for advanced functional devices. Recently, single-atom devices have been proposed as the ultimate miniaturization of functional devices beyond the nanoscale; however, achieving an atomic-scale local electromechanical response is still challenging due to physical size lim...

The transverse thermoelectric effect based on the anomalous Nernst effect (ANE) has attracted attention, especially for thermoelectric and spintronic applications. Fe3X (X = Ga, Al) is known to exhibit a large ANE at room temperature owing to the topological electronic band structure so-called nodal web. Here, we systematically investigate ANE in t...

Giant magnetic transverse thermoelectric effect, anomalous Nernst effect (ANE), was theoretically and experimentally observed in 3d-transition metal compounds. The intrinsic components of ANE can be described from the electronic structure based on the Berry phase concept. The topological electronic structure, such as the Weyl node and nodal lines,...

We develop a high-throughput computational scheme based on cluster multipole theory to identify new functional antiferromagnets (AFMs). This approach is applied to 228 magnetic compounds listed in the AtomWork-Adv database, known for their elevated Néel temperatures. We conduct systematic investigations of both stable and metastable magnetic config...

Strain engineering is a crucial approach in the engineering field to optimize various physical properties of materials by applying mechanical strain loading. However, it is extremely challenging to find out the best conditions of strain with unprecedented physical properties in the vast strain space consisting of six components. Here, we developed...

DOI:https://doi.org/10.1103/PhysRevB.108.239902

Brittle fracture of a covalent material is ultimately governed by the strength of the electronic bonds. Recently, attempts have been made to alter the mechanical properties including fracture strength by excess electron/hole doping. However, the underlying mechanics/mechanism of how these doped electrons/holes interact with the bond and changes its...

The mechanical response of ferroelectric (piezoelectric) ceramics under high stress conditions has a crucial role from the perspective of engineering applications such as advanced actuator systems. In this study, we perform first-principles calculations to clarify the deformation behavior and (ideal) tensile strength for typical ferroelectric ceram...

Magnetic materials exhibit various magnetic orders and are used in many magnetic and mechanical devices. In order to control and design magnetic ordering, the stability of the magnetic phase with mechanical strain has been reported in previous studies. In this study, based on the first-principles calculation, we investigate the stain dependence of...

Giant anomalous Hall effect (AHE) and magneto-optical activity can emerge in magnets with topologically nontrivial degeneracies. However, identifying the specific band-structure features such as Weyl points, nodal lines, or planes which generate the anomalous response is a challenging issue. Since the low-energy interband transitions can govern the...

In ferromagnets, an electric current generally induces a transverse Hall voltage in proportion to the internal magnetization. This effect is frequently used for the electrical readout of the spin-↑ and spin-↓ states. Although these properties are usually not expected in antiferromagnets, recent theoretical studies predicted that a non-coplanar anti...

Giant anomalous Hall effect (AHE) and magneto-optical activity can emerge in magnets with topologically non-trivial degeneracies. However, identifying the specific band structure features like Weyl points, nodal lines or planes which generate the anomalous response is a challenging issue. Since the low-energy interband transitions can govern the st...

We implemented a finite-difference algorithm for computing anomalous Hall and Nernst conductivity. Based on the expression to evaluate the Berry curvature in an insulating system [J. Phys. Soc. Jpn. 74, 1674 (2005)], we extended the methods to a metallic system. We calculated anomalous Hall conductivity and Nernst conductivity in a two-dimensional...

Thermoelectric conversion using the anomalous Nernst effect (ANE) has excellent potential for application in energy harvesting technology. Compared to the typical thermoelectric effect known as the Seebeck effect, the thermoelectric figure of merit in ANE is about ten times smaller; material search with a large ANE response is a critical challenge...

Recent discoveries of the topological magnets have opened a new path for developing a much simpler thermoelectric conversion module using the anomalous Nernst effect (ANE). To accelerate such innovation, it is essential to design materials suitable for industrial processes, and thus a high‐ANE polycrystalline material has been highly desired. Recen...

Geometrical aspects of electronic states in condensed matter have led to the experimental realization of enhanced electromagnetic phenomena, as exemplified by the giant anomalous Hall effect (AHE) in topological semimetals. However, the guideline to the large AHE is still immature due to lack of profound understanding of the sources of the Berry cu...

A large intrinsic anomalous Hall effect (AHE) originating in the Berry curvature has attracted growing attention for potential applications. The recently proposed magnetic Weyl semimetal EuCd2Sb2 provides an excellent platform for controlling the intrinsic AHE because it only hosts a Weyl-point-related band structure near the Fermi energy. Here, we...

Large intrinsic anomalous Hall effect (AHE) originating in the Berry curvature has attracted growing attention for potential applications. Recently proposed magnetic Weyl semimetal EuCd$_2$Sb$_{\mathrm{2}}$ provides an excellent platform for controlling the intrinsic AHE because it only hosts a Weyl-points related band structure near the Fermi ener...

In this study, we implemented a finite-difference algorithm for computing anomalous Hall and Nernst conductivity. Based on the expression to evaluate the Berry curvature in an insulating system [J. Phys. Soc. Jpn. 74 1674(2005)], we extended the methods to a metallic system. We calculated anomalous Hall conductivity and Nernst conductivity in a two...

We study the mechanism of the exceptionally large anomalous Hall effect (AHE) in the noncentrosymmetric antiferromagnet CoNb3S6 by angle-resolved photoemission spectroscopy (ARPES) and magnetotransport measurements. From ARPES measurements of CoNb3S6 and its family compounds (FeNb3S6 and NiNb3S6), we find a band dispersion unique to the Co intercal...

Noncollinear antiferromagnets Mn 3 X ( X = Sn, Ge) are characterized by a large anomalous Hall effect originating from a large Berry curvature despite a vanishingly small magnetization. From recent first-principle theories, the large Berry curvature is predicted to be induced by a existence of Weyl nodes broken time-reversal symmetry. The large ano...

We study the mechanism of the exceptionally large anomalous Hall effect (AHE) in the noncentrosymmetric antiferromagnet $\mathrm{Co}\mathrm{Nb}_3\mathrm{S}_6$ by angle-resolved photoemission spectroscopy (ARPES) and magnetotransport measurements. From ARPES measurements of $\mathrm{Co}\mathrm{Nb}_3\mathrm{S}_6$ and its family compounds ($\mathrm{Fe...

Anomalous Nernst effect (ANE), converting a heat flow to transverse electric voltage, originates from the Berry phase of electronic wave function near the Fermi energy EF. Thus, the ANE provides a sensitive probe to detect a topological state that produces large Berry curvature. In addition, a magnet that exhibits a large ANE using low-cost and saf...

The recent discoveries of strikingly large zero-field Hall and Nernst effects in antiferromagnets Mn3X (X = Sn, Ge) have brought the study of magnetic topological states to the forefront of condensed matter research and technological innovation. These effects are considered fingerprints of Weyl nodes residing near the Fermi energy, promoting Mn3X (...

We report the results of our experimental studies on the magnetic, transport, and thermoelectric properties of the ferromagnetic metal CoMnSb. A sizable anomalous Hall conductivity σyx and transverse thermoelectric conductivity αyx are found experimentally and comparable in size to the values estimated from first-principles calculation. Our experim...

We report the results of our experimental studies on the magnetic, transport and thermoelectric properties of the ferromagnetic metal CoMnSb. Sizable anomalous Hall conductivity $\sigma_{yx}$ and transverse thermoelectric conductivity $\alpha_{yx}$ are found experimentally and comparable in size to the values estimated from density-functional theor...

We report fabrication of EuSb2 single-crystalline films and investigation of their quantum transport. First-principles calculations demonstrate that EuSb2 is a magnetic topological nodal-line semimetal protected by nonsymmorphic symmetry. Observed Shubnikov-de Haas oscillations with multiple frequency components exhibit small effective masses and t...

We report fabrication of EuSb$_2$ single-crystalline films and investigation of their quantum transport. First-principles calculations demonstrate that EuSb$_2$ is a magnetic topological nodal-line semimetal protected by nonsymmorphic symmetry. Observed Shubnikov-de Haas oscillations with multiple frequency components exhibit small effective masses...

Motivated by the recent discovery of a large anomalous Nernst effect in Co2MnGa, Fe3X (X=Al, Ga) and Co3Sn2S2, we performed a first-principles study to clarify the origin of the enhancement of the transverse thermoelectric conductivity αij in these ferromagnets. The intrinsic contribution to αij can be understood in terms of the Berry curvature Ω a...

The recent discoveries of strikingly large zero-field Hall and Nernst effects in antiferromagnets Mn$_3$$X$, ($X$ = Sn, Ge) have brought the study of magnetic topological states to the forefront of condensed matter research and technological innovation. These effects are considered fingerprints of Weyl nodes residing near the Fermi energy, promotin...

Magnetic Weyl semimetals attract considerable interest not only for their topological quantum phenomena but also as an emerging materials class for realizing quantum anomalous Hall effect in the two-dimensional limit. A shandite compound Co3Sn2S2 with layered Kagome-lattices is one such material, where vigorous efforts have been devoted to synthesi...

The Weyl semimetal (WSM), which hosts pairs of Weyl points and accompanying Berry curvature in momentum space near Fermi level, is expected to exhibit novel electromagnetic phenomena. Although the large optical/electronic responses such as nonlinear optical effects and intrinsic anomalous Hall effect (AHE) have recently been demonstrated indeed, th...

Magnetic Weyl semimetals attract considerable interest not only for their topological quantum phenomena but also as an emerging materials class for realizing quantum anomalous Hall effect in the two-dimensional limit. A shandite compound Co3Sn2S2 with layered Kagome-lattices is one such material, where vigorous efforts have been devoted to synthesi...

Motivated by the recent discovery of a large anomalous Nernst effect in Co$_2$MnGa, Fe$_3X$ ($X$=Al, Ga) and Co$_3$Sn$_2$S$_2$, we performed a first-principles study to clarify the origin of the enhancement of the transverse thermoelectric conductivity ($\alpha_{ij}$) in these ferromagnets. The intrinsic contribution to $\alpha_{ij}$ can be underst...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Half-Heusler (HH) alloys are an important and well-studied class of thermoelectric, magnetic, and spintronic materials. However, few studies have reported on thermal conductivity of magnetic HH alloys. In this study, we have performed first-principles calculation of the thermoelectric properties of a magnetic HH alloy CoMnSb. The lattice thermal co...

Thermoelectric generation using the anomalous Nernst effect (ANE) has great potential for application in energy harvesting technology because the transverse geometry of the Nernst effect should enable efficient, large-area and flexible coverage of a heat source. For such applications to be viable, substantial improvements will be necessary not only...

We performed first-principles simulations to elucidate the transverse thermoelectric effect (anomalous Nernst effect) of the half-metallic FeCl2 monolayer. We analyzed its thermoelectricity based on the semiclassical transport theory including the effect of Berry curvature and found that carrier-doping induced a large anomalous Nernst effect that w...

We have performed systematic density functional calculations and evaluated thermoelectric properties, See- beck coefficient and anomalous Nernst coefficient of half-Heusler comounds CoMSb(M=Sc, Ti, V, Cr, and Mn). The carrier concentration dependence of Seebeck coefficients in nonmagnetic compounds are in good agreement with experimental values. We...

Two-dimensional hexagonal materials such as graphene and silicene have highly symmetric crystal structures and Dirac cones at the K point, which induce novel electronic properties. In this report, we calculate their electronic structures by using density functional theory and analyze their band structures on the basis of the group theory. Dirac con...