SrIrO3, the three-dimensional member of the Ruddlesden-Popper iridates, is a paramagnetic semimetal characterised by a the delicate interplay between spin-orbit coupling and Coulomb repulsion. In this work, we study the anisotropic magnetoresistance (AMR) of SrIrO3 thin films, which is closely linked to spin-orbit coupling and probes correlations between electronic transport, magnetic order and orbital states. We show that the low-temperature negative magnetoresistance is anisotropic with respect to the magnetic field orientation, and its angular dependence reveals the appearance of a fourfold symmetric component above a critical magnetic field. We show that this AMR component is of magnetocrystalline origin, and attribute the observed transition to a field-induced magnetic state in SrIrO3.
Extremely large positive magnetoresistance (XMR) was found in a nonmagnetic semimetal InBi. Using several single crystals with different residual resistivity ratios (RRRs), we revealed that the XMR strongly depended on the RRR (sample quality). Assuming that there were no changes in effective mass m* and carrier concentrations in these single crystals, this dependence was explained by a semiclassical two-carrier model. First-principle calculations including the spin-orbit interactions (SOI) unveiled that InBi had a compensated carrier balance and SOI-induced "hidden" three-dimensional (3D) Dir…
The discovery of non-magnetic extreme magnetoresistance (XMR) materials has induced great interests because the XMR phenomenon challenges our understanding of how a magnetic field can alter electron transport in semimetals. Among XMR materials, the LaSb shows XMR and field-induced exotic behaviors but it seems to lack the essentials for these properties. Here, we study the magnetotransport properties and electronic structure of LaBi, isostructural to LaSb. LaBi exhibits large MR as in LaSb, which can be ascribed to the nearly compensated electron and hole with rather high mobilities. More impo…
Topological materials with extremely large magnetoresistance exhibit a prognostic feature of resistivity turn-on behaviour. This occurs when the temperature dependence of resistivity changes from metallic to semiconducting characteristics on application of external magnetic field above a threshold value. Here, we study the magneto-transport properties of type-II Weyl Semimetal WP2. We find that semi-classical theories of magnetoresistance are consistent with our data without the need to invoke topological surface states. Our findings in this work provides an alternative basis to understand the…
Negative magnetoresistance (NMR) induced by the Adler-Bell-Jackiw anomaly is regarded as the most prominent quantum signature of Weyl semimetals when electrical field $E$ is collinear with the external magnetic field $B$. In this article, we report universal NMR in nonmagnetic, centrosymmetric transition metal dipnictides MPn$_{2}$ (M=Nb and Ta; Pn=As and Sb), in which the existence of Weyl fermions can be explicitly excluded. Using temperature-dependent magnetoresistance, Hall and thermoelectric coefficients of Nernst and Seebeck effects, we determine that the emergence of the NMR phenomena i…
The combination of magnetic symmetries and electronic band topology provides a promising route for realizing topologically nontrivial quasiparticles, and the manipulation of magnetic structures may enable the switching between topological phases, with the potential for achieving functional physical properties. Here, we report measurements of the electrical resistivity of EuCd$_2$As$_2$ under pressure, which show an intriguing insulating dome at pressures between $p_{\rm c1}\sim1.0$~GPa and $p_{\rm c2}\sim2.0$~GPa, situated between two regimes with metallic transport. The insulating state can b…
We instigate the angle-dependent magnetoresistance (AMR) of the layered nodal-line Dirac semimetal ZrSiS for the in-plane and out-of-plane current directions. This material has recently revealed an intriguing butterfly-shaped in-plane AMR that is not well understood. Our measurements of the polar out-of-plane AMR show a surprisingly different response with a pronounced cusp-like feature. The maximum of the cusp-like anisotropy is reached when the magnetic field is oriented in the $a$-$b$ plane. Moreover, the AMR for the azimuthal out-of-plane current direction exhibits a very strong four-fold …
We report a detailed magnetotransport study on single crystals of PrBi. The presence of $f$-electrons in this material raises the prospect of realizing a strongly correlated version of topological semimetals. PrBi shows a magnetic field induced metal insulator transition below $T \sim 20$ K and a very large magnetoresistance ($\approx 4.4 \times 10^4~$) at low temperatures ($T= 2$ K). We have also probed the Fermi surface topology by de Haas van Alphen (dHvA) and Shubnikov de Haas (SdH) quantum oscillation measurements complimented with density functional theory (DFT) calculations of the band …
Recent experiments on type-II Weyl semimetals such as WTe$_2$, MoTe$_2$, Mo$_x$W$_{1-x}$Te$_2$ and WP$_2$ reveal remarkable transport properties in presence of a strong magnetic field, including an extremely large magnetoresistance and an unusual temperature dependence. Here, we investigate magnetotransport via the Kubo formula in a minimal model of a type-II Weyl semimetal taking into account the effect of a charge density wave (CDW) transition, which can arise even at weak coupling in the presence of a strong magnetic field because of the special Landau level dispersion of type-II Weyl syste…
We systematically measured the Hall effect in the extremely large magnetoresistance semimetal WTe$_2$. By carefully fitting the Hall resistivity to a two-band model, the temperature dependencies of the carrier density and mobility for both electron- and hole-type carriers were determined. We observed a sudden increase of the hole density below $\sim$160~K, which is likely associated with the temperature-induced Lifshitz transition reported by a previous photoemission study. In addition, a more pronounced reduction in electron density occurs below 50~K, giving rise to comparable electron and ho…
The transverse and longitudinal magnetoresistance (MR) of two samples of the topological chiral semimetal CoSi with different RRR was studied. It is shown that the Kohler rule works for the transverse MR. The Kohler rule is also fulfilled in the case of longitudinal MR at a low reduced magnetic field. A sharp deviation of longitudinal MR curve for sample with low RRR from the Kohler prediction at high fields reveals its tendency to a sign change at higher magnetic fields. The Shubnikov de Haas quantum oscillations were observed and analyzed in both perpendicular and parallel configurations of …
A large negative magnetoresistance is anticipated in topological semimetals in the parallel magnetic and electric field configuration as a consequence of the nontrivial topological properties. The negative magnetoresistance is believed to demonstrate the chiral anomaly, a long-sought high-energy physics effect, in solid-state systems. Recent experiments reveal that Cd3As2, a Dirac topological semimetal, has the record-high mobility and exhibits positive linear magnetoresistance in the orthogonal magnetic and electric field configuration. However, the negative magnetoresistance in the parallel …
Incommensurate magnetic order drives singular angular magnetoresistance in a Weyl semimetal
Boston College（波士顿学院）；NIST Center for Neutron Research, National Institute of Standards and Technology（美国国家标准与技术研究院中子研究中心）；Tata Institute of Fundamental Research（塔塔基础研究所）；University of California, Los Angeles（加州大学洛杉矶分校）；Oak Ridge National Laboratory（橡树岭国家实验室）；National Synchrotron Radiation Research Center（国家同步辐射研究中心）；ISIS neutron and muon source, STFC, Rutherford Appleton Laboratory（STFC卢瑟福阿普尔顿实验室ISIS中子和缪子源）；J-PARC Center, Japan Atomic Energy Agency（日本原子能机构J-PARC中心）；University of Tsukuba（筑波大学）
We performed the angle dependent magnetoresistance (MR), Hall effect measurements, the temperature dependent magneto-thermoelectric power (TEP) S(T) measurements, and the first-principles calculations to study the electronic properties of orthorhombic phase MoTe2 (Td-MoTe2), which was proposed to be electronically two-dimensional (2D). There are some interesting findings about Td-MoTe2: (1) A scaling approach εθ=(sin2θ+γ-2cos2θ)1/2 is applied, where θ is the magnetic field angle with respect to the c axis of the crystal and γ is the mass anisotropy. Unexpectedly, the electronically 3D characte…
While recent advances in band theory and sample growth have expanded the series of extremely large magnetoresistance (XMR) semimetals in transition metal dipnictides $TmPn_2$ ($Tm$ = Ta, Nb; $Pn$ = P, As, Sb), the experimental study on their electronic structure and the origin of XMR is still absent. Here, using angle-resolved photoemission spectroscopy combined with first-principles calculations and magnetotransport measurements, we performed a comprehensive investigation on MoAs$_2$, which is isostructural to the $TmPn_2$ family and also exhibits quadratic XMR. We resolve a clear band struct…
Antiferromagnetic spintronics actively introduces new principles of magnetic memory, in which the most fundamental spin-dependent phenomena, i.e. anisotropic magnetoresistance effects, are governed by an antiferromagnet instead of a ferromagnet. A general scenario of the antiferromagnetic anisotropic magnetoresistance effects mainly stems from the magnetocrystalline anisotropy related to spin-orbit coupling. Here we demonstrate magnetic field driven contour rotation of the fourfold anisotropic magnetoresistance in bare antiferromagnetic Sr2IrO4/SrTiO3 (001) thin films hosting a strong spin-orb…
The impact of carrier localization on the anisotropic magnetoresistance (AMR) has been investigated in NSSMO thin films. Carrier localization is caused by the reduced average radius of the A-site of the perovskite lattice and enhanced size disorder due to substitution of smaller cations for larger.
We present a theory of thermoelectric transport in weakly disordered Weyl semimetals where the electron-electron scattering time is faster than the electron-impurity scattering time. Our hydrodynamic theory consists of relativistic fluids at each Weyl node, coupled together by perturbatively small inter-valley scattering, and long-range Coulomb interactions. The conductivity matrix of our theory is Onsager reciprocal and positive-semidefinite. In addition to the usual axial anomaly, we account for the effects of a distinct, axial-gravitational anomaly expected to be present in Weyl semimetals.…
We report the effect of Dirac cone tilting on interlayer magnetoresistance in α-(BEDT-TTF)$_2$I$_3$, which is a Dirac semimetal under pressure. Fitting of the experimental data by the theoretical formula suggests that the system is close to a type-II Dirac semimetal.
Weyl semimetal with Weyl fermions at Fermi energy is one of the topological materials, and is a condensed-matter realization of the relativistic fermions. However, there are several crucial differences such as the shift of Fermi energy, which can hinder the expected interesting physics. Chiral anomaly is a representative nontrivial phenomenon associated with Weyl fermions, which dictates the transfer of fermions between the Weyl fermions with opposite chirality; it is manifested as the negative magnetoresistance. Here we demonstrate that the magnetoresistance is robust against the deviation fr…
The rapidly expanding class of quantum materials known as {\emph{topological semimetals}} (TSM) display unique transport properties, including a striking dependence of resistivity on applied magnetic field, that are of great interest for both scientific and technological reasons. However, experimental signatures that can identify or discern the dominant mechanism and connect to available theories are scarce. Here we present the magnetic susceptibility ($χ$), the tangent of the Hall angle ($\tanθ_H$) along with magnetoresistance in four different non-magnetic semimetals with high mobilities, Nb…
Dirac semimetals and Weyl semimetals are 3D analogs of graphene in which crystalline symmetry protects the nodes against gap formation [1-3]. Na$_3$Bi and Cd$_3$As$_2$ were predicted to be Dirac semimetals [4,5], and recently confirmed to be so by photoemission [6-8]. Several novel transport properties in a magnetic field $\bf H$ have been proposed for Dirac semimetals [2,9-11]. Here we report an interesting property in Cd$_3$As$_2$ that was unpredicted, namely a remarkable protection mechanism that strongly suppresses back-scattering in zero $\bf H$. In single crystals, the protection results…
We report a comprehensive investigation of the structural, magnetic, transport and thermodynamic properties of a single crystal PrAlSi, in comparison to its nonmagnetic analogue LaAlSi. PrAlSi exhibits a ferromagnetic transition at $T_C$ = 17.8 K which, however, is followed by two weak phase transitions at lower temperatures. Based on the combined dc and ac magnetic susceptibility measurements, we propose the two reentrant magnetic phases below $T_C$ to be spin glasses or ferromagnetic cluster glasses. When the magnetic glassy states are suppressed by small field, several remarkable features a…
Time reversal symmetry (TRS) protects the metallic surface modes of topological insulators (TIs). The transport signature of robust metallic surface modes of TIs is a plateau that arrests the exponential divergence of the insulating bulk with decreasing temperature. This universal behavior is observed in all TI candidates ranging from Bi2Te2Se to SmB6. Recently, several topological semimetals (TSMs) have been found that exhibit extreme magnetoresistance (XMR) and TI universal resistivity behavior revealed only when breaking TRS, a regime where TIs theoretically cease to exist. Among these new …
MBE-grown, 5 nm-thick annealed Ga0.95Mn0.05As films with Tc~90K demonstrate transition from metallic to insulating state below To~10K, where sheet resistances Rsh~h/e2 and both longitudinal Rxx and transverse Rxy components become comparable. Below metal-insulator transition we found giant anisotropic magnetoresistance (GAMR), which depends on orientation of magnetization to crystallographic axes and manifests itself in positive magnetoresistance near 50% for Rxx at T=1.7K, H//[110] crystallographic direction and parallel to current in contrast to smaller and negative magnetoresistance for H//…
We report the first experimental results of the magnetoresistance, Hall effect, and quantum Shubnikov-de Haas oscillations on single crystals of ZrTe, which was recently predicted to be a new type of topological semimetal hosting both triply degenerate crossing points and Weyl fermion state. The analysis of Hall effect and quantum oscillations indicate that ZrTe is a multiband system with low carrier density, high carrier mobility, small cross-sectional area of Fermi surface, and light cyclotron effective mass, as observed in many topological semimetals. Meanwhile, the angular dependence of th…
High-quality nonmagnetic half-Heusler ScPtBi single crystals were synthesized by a Bi self-flux method. This compound was revealed to be a hole-dominated semimetal with a large low-field magnetoresistance up to 240% at 2K in a magnetic field of 1T. Magneto-transport measurements demonstrated that the large low-field magnetoresistance effect resulted from the coexistence of field-induced metal-semiconductor transition and weak-antilocalization effect. Moreover, Hall measurements indicated that ScPtBi single crystal showed a high mobility over a wide temperature region even up to room temperatur…
The resistance of a metal in a magnetic field can be very illuminating about its ground state. Some famous examples include the integer and fractional quantum Hall effects\cite{Klitzing-QHE,Tsui-FQHE}, Shubnikov-de Haas oscillations\cite{SdH}, and weak localization\cite{Lee-WL} \emph{et al}. In non-interacting metals the resistance typically increases upon the application of a magnetic field\cite{Pippard-MR}. In contrast, in some special circumstances metals, with anisotropic Fermi surfaces\cite{Kikugawa-PdCoO2LMR} or a so-called Weyl semimetal for instance\cite{Nielsen-ABJ,Son-ChirAnom}, may …
Two-component conductors -- e.g., semi-metals and narrow band semiconductors -- often exhibit unusually strong magnetoresistance in a wide temperature range. Suppression of the Hall voltage near charge neutrality in such systems gives rise to a strong quasiparticle drift in the direction perpendicular to the electric current and magnetic field. This drift is responsible for a strong geometrical increase of resistance even in weak magnetic fields. Combining the Boltzmann kinetic equation with sample electrostatics, we develop a microscopic theory of magnetotransport in two and three spatial dim…
The acute sensitivity of the electrical resistance of certain systems to magnetic fields known as extreme magnetoresistance (XMR) has recently been explored in a new materials context with topological semimetals. Exemplified by WTe$_{2}$ and rare earth monopnictide La(Sb,Bi), these systems tend to be non-magnetic, nearly compensated semimetals and represent a platform for large magnetoresistance driven by intrinsic electronic structure. Here we explore electronic transport in magnetic members of the latter family of semimetals and find that XMR is strongly modulated by magnetic order. In parti…
We report transverse and longitudinal magneto-transport properties of NbAs2 single crystals. Attributing to the electron-hole compensation, non-saturating large transverse magnetoresistance reaches up to 8000 at 9 T at 1.8 K with mobility around 1 to 2 m^2V^-1S^-1. We present a thorough study of angular-dependent Shubnikov-de Haas (SdH) quantum oscillations of NbAs2. Three distinct oscillation frequencies are identified. First-principles calculations reveal four types of Fermi pockets: electron alpha pocket, hole beta pocket, hole gamma pocket and small electron delta pocket. Although the angu…
We report a detailed magneto-transport study in single crystals of NbP. High quality crystals were grown by vapour transport method. An exceptionally large magnetoresistance is confirmed at low temperature which is non-saturating and is linear at high fields. Models explaining the linear magnetoresistance are discussed and it is argued that in NbP this is linked to charge carrier mobility fluctuations. Negative longitudinal magnetoresistance is not seen, unlike several other Weyl monopnictides, suggesting lack of well defined chiral anomaly in NbP. Unambiguous Shubnikov-de-Haas oscillations ar…
In this work we report the results of DC susceptibility, AC susceptibility and related technique, resistivity, transverse and longitudinal magnetoresistance and heat capacity on polycrystalline magnetic semimetal CeAlGe. This compound undergoes antiferromagnetic type ordering around 5.2 K (T1). Under application of external magnetic fields, parallel alignment of magnetic moments is favored, above 0.5 Tesla. At low field and temperature, frequency and AC field amplitude response of AC susceptibility indicate to the presence of spin-lattice relaxation phenomena. The observation of spin-lattice i…
Extremely large magnetoresistance (XMR) was recently discovered in many non-magnetic materials, while its underlying mechanism remains poorly understood due to the complex electronic structure of these materials. Here, we report an investigation of the $α$-phase WP$_2$, a topologically trivial semimetal with monoclinic crystal structure (C2/m), which contrasts to the recently discovered robust type-II Weyl semimetal phase in $β$-WP$_2$. We found that $α$-WP$_2$ exhibits almost all the characteristics of XMR materials: the near-quadratic field dependence of MR, a field-induced up-turn in resist…
The newly discovered topological Dirac semimetals host the possibilities of various topological phase transitions through the control of spin-orbit coupling as well as symmetries and dimensionalities. Here, we report a magnetotransport study of high-mobility (Cd1-xZnx)3As2 films, where the topological Dirac semimetal phase can be turned into a trivial insulator via chemical substitution. By high-field measurements with a Hall-bar geometry, magnetoresistance components ascribed to the chiral charge pumping have been distinguished from other extrinsic effects. The negative magnetoresistance exhi…
Weyl semimetals, characterized by nodal points in the bulk and Fermi arc states on the surface, have recently attracted extensive attention due to the potential application on low energy consumption electronic materials. In this report, the thermodynamic and transport properties of a theoretically predicted Weyl semimetal NbIrTe4 is measured in high magnetic fields up to 35 T and low temperatures down to 0.4 K. Remarkably, NbIrTe4 exhibits a nonsaturating transverse magnetoresistance which follows a power-law dependence in B. Low-field Hall measurements reveal that hole-like carriers dominate …
We performed calculations of the electronic band structure and the Fermi surface as well as measured the longitudinal resistivity $ρ_{xx}(T,H)$, Hall resistivity $ρ_{xy}(T,H)$, and magnetic susceptibility as a function of temperature and various magnetic fields for VAs$_2$ with a monoclinic crystal structure. The band structure calculations show that VAs$_2$ is a nodal-line semimetal when spin-orbit coupling is ignored. The emergence of a minimum at around 11 K in $ρ_{xx}(T)$ measured at $H$ = 0 demonstrates that an additional magnetic impurity (V$^{4+}$, $S$ = 1/2) occurs in VAs$_2$ single cr…
After growing successfully TaP single crystal, we measured its longitudinal resistivity (rhoxx) and Hall resistivity (rhoyx) at magnetic fields up to 9T in the temperature range of 2-300K. It was found that at 2K its magnetoresistivity (MR) reaches to 328000 percent, at 300K to 176 percent at 8T, and both do not appear saturation. We confirmed that TaP is indeed a low carrier concentration, hole-electron compensated semimetal, with a high mobility of hole muh=371000 cm2V-1s-1, and found that a magnetic-field-induced metal-insulator transition occurs at room temperature. Remarkably, as a magnet…
Weyl semimetals such as the TaAs family (TaAs, TaP, NbAs, NbP) host quasiparticle excitations resembling the long sought after Weyl fermions at special band-crossing points in the band structure denoted as Weyl nodes. They are predicted to exhibit a negative longitudinal magnetoresistance (LMR) due to the chiral anomaly if the Fermi energy is sufficiently close to the Weyl points. However, current jetting effects, i.e. current inhomogeneities caused by a strong, field-induced conductivity anisotropy in semimetals, have a similar experimental signature and therefore have hindered a determinatio…
Layered van der Waals semimetallic $T_\mathrm{d}$-WTe$_{2}$, exhibiting intriguing properties which include non-saturating extreme positive magnetoresistance (MR) and tunable chiral anomaly, has emerged as model topological type-II Weyl semimetal system. Here, $\sim$45 nm thick mechanically exfoliated flakes of $T_\mathrm{d}$-WTe$_{2}$ are studied $via$ atomic force microscopy, Raman spectroscopy, low-$T$/high-$μ_{0}H$ magnetotransport measurements and optical reflectivity. The contribution of anisotropy of the Fermi liquid state to the origin of the large positive transverse $\mathrm{MR}_\per…
In the Dirac/Weyl semimetal, the chiral anomaly appears as an "axial" current arising from charge-pumping between the lowest (chiral) Landau levels of the Weyl nodes, when an electric field is applied parallel to a magnetic field $\bf B$. Evidence for the chiral anomaly was obtained from the longitudinal magnetoresistance (LMR) in Na$_3$Bi and GdPtBi. However, current jetting effects (focussing of the current density $\bf J$) have raised general concerns about LMR experiments. Here we implement a litmus test that allows the intrinsic LMR in Na$_3$Bi and GdPtBi to be sharply distinguished from …
Magnetoresistance in Magnetic Weyl semimetal Mn$_{3}$ZnC
School of Physical Sciences, Indian Institute of Technology Mandi（印度技术学院曼迪分校物理科学学院）；Center for Quantum Science and Technologies, Indian Institute of Technology Mandi（印度技术学院曼迪分校量子科学与技术中心）
A number of rare-earth monopnictides have topologically non-trivial band structures together with magnetism and strong electronic correlations. In order to examine whether the antiferromagnetic (AFM) semimetal YbAs ($T\rm_N$ = 0.5 K) exhibits such a scenario, we have grown high-quality single crystals using a flux method, and characterized the magnetic properties and electronic structure using specific heat, magnetotransport and angle-resolved photoemission spectroscopy (ARPES) measurements, together with density functional theory (DFT) calculations. Both ARPES and DFT calculations find no evi…
The effective low energy description of interacting Dirac and Weyl semimetals is that of massless quantum electrodynamics with several Lorentz breaking material parameters. We perform a renormalization group analysis of Coulomb interaction in anisotropic Dirac and Weyl semimetals and show that the anisotropy persists in the material systems at the infrared fixed point. In addition, a tilt of the fermion cones breaking inversion symmetry induces a magnetoelectric term in the electrodynamics of the material whose magnitude runs to match that of the electronic tilt at the fixed point.
We report the magnetoresistance of a charge-density wave (CDW) in $o$-TaS$_3$ whiskers at 4.2 K under a magnetic field up to 5.2 T. An anisotropic negative magnetoresistance is found in the nonlinear regime of current-voltage characteristics. The angle dependence of the magnetoresistance, studied by rotating the magnetic field upon the $c$-axis, exhibited a two-fold symmetry. The magnetoresistance amplitude exhibits maxima when the field is parallel to the $a$-axis, whereas it vanishes to the $b$-axis. The observed anisotropy may come from difference in interchain coupling of adjacent CDWs alo…
Taking into account the interplay between the disorder and Coulomb interaction, the phase diagram of three-dimensional anisotropic Weyl semimetal is studied by renormalization group theory. Weak disorder is irrelevant in anisotropic Weyl semimetal, while the disorder becomes relevant and drives a quantum phase transition from semimetal to compressible diffusive metal phases if the disorder strength is larger than a critical value. The long-range Coulomb interaction is irrelevant in clean anisotropic Weyl semimetal. However, interestingly, we find that the long-range Coulomb interaction exerts …
A systematic study of the temperature and magnetic field dependence of the longitudinal and transverse resistivities of epitaxial thin films of magnetite (Fe3O4) is reported. The anisotropic magnetoresistance (AMR) and the planar Hall effect (PHE) are sensitive to the in-plane orientation of current and magnetization with respect to crystal axes in a way consistent with the cubic symmetry of the system. We also show that the AMR exhibit sign reversal as a function of temperature, and that it shows significant field dependence without saturation up to 9 T. Our results provide a unified descript…
The behavior of charge density wave (CDW) in an external magnetic field is dictated by both orbital and Pauli (Zeeman) effects. A quasi-one-dimensional (Q1D) system features Q1D Fermi surfaces that allow these effects to be distinguished, which in turn can provide sensitive probe to the underlying electronic states. Here we studied the field dependence of an incommensurate CDW in a transition-metal chalcogenide Ta2NiSe7 with a Q1D chain structure. The angle-dependent magnetoresistance (MR) is found to be very sensitive to the relative orientation between the magnetic field and the chain direct…
We report the discovery of giant and anisotropic magnetoresistance due to the orbital rearrangement in a non-magnetic correlated metal. In particular, we measured the magnetoresistance under fields up to 31.4 T in the cubic Pr-based heavy fermion superconductor PrV$_2$Al$_{20}$ with a non-magnetic $Γ_3$ doublet ground state, exhibiting antiferro-quadrupole ordering below 0.7 K. For the [100] direction, we find that the high-field phase appears between 12 T and 25 T, accompanied by a large jump at 12 T in the magnetoresistance ($ΔMR \sim $ 100 $\% $) and in the anisotropic magnetoresistivity (A…
EuB6 is a low carrier density ferromagnet which exhibits large magnetoresistance, positive or negative depending on temperature. The formation of magnetic polarons just above the magnetic critical temperature has been suggested by spin-flip Raman scattering experiments. We find that the fact that EuB6 is a semimetal has to be taken into account to explain its electronic properties, including magnetic polarons and magnetoresistance.
We measured the magnetoresistance of the 2D electron liquid formed at the (111) LaAlO$_3$/SrTiO$_3$ interface. The hexagonal symmetry of the interface is manifested in a six-fold crystalline component appearing in the anisotropic magnetoresistance (AMR) and planar Hall data, which agree well with symmetry analysis we performed. The six-fold component increases with carrier concentration, reaching 15% of the total AMR signal. Our results suggest the coupling between higher itinerant electronic bands and the crystal as the origin of this effect and demonstrate that the (111) oxide interface is a…
We have investigated the anisotropy of the magnetoresistance in the Pr-based HF compound PrFe4P12. The large anisotropy of effective mass and its strong field dependence have been confirmed by resistivity measurements. Particularly for H||[111], where the effective mass is most strongly enhanced, the non-Fermi liquid behavior has been observed. Also, we have found the angular dependence of the magnetoresistance sharply enhanced at H||[111], which is evidently correlated with both the non-Fermi liquid behavior and the high-field ordered state (B-phase).
