Electrical and thermal magnetotransport in altermagnetic CrSb

Abstract

Chromium antimonide has emerged as a key material platform for studying altermagnetism because of its simple binary composition, high Néel temperature, and semimetallic electronic structure. Here, we investigate electrical and thermal magnetotransport in single-crystalline CrSb using steady-and pulsed-magnetic fields up to 65 T, and complement these measurements with neutron diffraction and magnetization data. We confirm the compensated magnetic structure and observe a large nonsaturating magnetoresistance together with a pronounced nonlinear Hall response at low temperatures. Multicarrier modeling, supported by mobility-spectrum analysis, reveals coexisting electron- and hole-like charge carriers with mobilities up to ~3000 cm2/Vs and shows that the number of transport channels that can be resolved strongly depends on the accessible magnetic-field range. Thermal-transport measurements further reveal a nonlinear thermal Hall response and a thermal conductivity substantially exceeding a simple Wiedemann-Franz law. The broadly similar field and temperature evolution of electrical and thermal transport point to a dominant electronic contribution, while the remaining deviations indicate additional heat-carrying channels.

Figures (9)

• Figure 1: Characterization of single crystals of CrSb: (a) Optical image of bulk CrSb single crystal with [0001]/$c$ axis perpendicular to the surface. The axes $[10\bar{1}0]$/$a^{*}$,[0001]/$c$ and $[\bar{1}100]$ are indicated. Blue axes indicate reciprocal lattice directions, whereas orange indicates real space directions. (b) Room temperature backscattered Laue diffraction pattern obtained from a flat single crystal. (c) Room-temperature powder x-ray diffraction pattern of CrSb. The inset shows the hexagonal unit cell of CrSb together with its magnetic structure (visualized using vestaMomma2011). The magnetic moments of the chromium atoms are directed along the $c$ axis.
• Figure 2: Determination of the Néel temperature: (a) Zero-field resistance from 300 to 850 K of a bulk CrSb single crystal (inset), showing $T_\mathrm{N} \approx 700$ K. (b) Differential scanning calorimetry thermograms of CrSb from 300K to 1000K. (c) Magnetization of CrSb measured from room temperature to 1000 K with magnetic fields of 0.1 T and 8 T, indicating a Néel temperature of about 700 K. (d) Magnetization at 5 K for magnetic fields applied along $c$ as well as perpendicular to c within the basal plane.
• Figure 3: Electrical transport measurements: (a) Optical images of the Hall bar bulk sample S2 and the multiterminal microstructure L1. Current is applied along the $a^{*}$ axis, and magnetic field is applied along the $c$ axis for both samples. (b) Longitudinal resistivity measured at 0 and 14 T. Inset: enlargement of the low temperature resistivity. The zero-field resistivity of L1 (grey) matches well with that of the bulk sample (light blue). (c, d) Magnetic-field dependence of the magnetoresistance and Hall resistivity of the sample S2 recorded at various fixed temperatures between 2 and 300K. (e, f) MR and Hall effect recorded in pulsed fields up to 65 T. We compare steady-field data recorded at 2 K (blue) and pulsed-field data at 4.2 K (black) for S2 with pulsed-field data of sample L1 measured at 4.2, 77, and 300 K, pink, green, brown, respectively.
• Figure 4: Multicarrier fitting of MR and Hall resistivity: Magnetic-field dependence of the longitudinal resistivity at 2 (a, c) and 300K (b, d), respectively. In all panels, the experimental data are compared to fits considering the contribution of 2, 3, and 4 individual types of charge carriers. Inset in (d): enlarged high-field range, highlighting the differences of the models.
• Figure 5: Multicarrier analysis: Temperature dependence of (a) the charge-carrier concentration and (b) mobility obtained from the four-band model fitting.