Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSrPd, a candidate material with extremely large magnetoresistance
376
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The extremely large magnetoresistance (XMR) effect in nonmagnetic semimetals have attracted intensive attention recently. Here we propose an XMR candidate material SrPd based on first-principles electronic structure calculations in combination with a semi-classical model. The calculated carrier densities in SrPd indicate that there is a good electron-hole compensation, while the calculated intrinsic carrier mobilities are as high as 10$^5$ cm$^2$V$^{-1}$s$^{-1}$. There are only two doubly degenerate bands crossing the Fermi level for SrPd, thus a semi-classical two-band model is available for describing its transport properties. Accordingly, the magnetoresistance of SrPd under a magnetic field of $4$ Tesla is predicted to reach ${10^5} %$ at low temperature. Furthermore, the calculated topological invariant indicates that SrPd is topologically trivial. Our theoretical studies suggest that SrPd can serve as an ideal platform to examine the charge compensation mechanism of the XMR effect.
rate research
Read More
Transition-metal dichalcogenides (WTe$_2$ and MoTe$_2$) have drawn much attention, recently, because of the nonsaturating extremely large magnetoresistance (XMR) observed in these compounds in addition to the predictions of likely type-II Weyl semimetals. Contrary to the topological insulators or Dirac semimetals where XMR is linearly dependent on the field, in WTe$_2$ and MoTe$_2$ the XMR is nonlinearly dependent on the field, suggesting an entirely different mechanism. Electron-hole compensation has been proposed as a mechanism of this nonsaturating XMR in WTe$_2$, while it is yet to be clear in the case of MoTe$_2$ which has an identical crystal structure of WTe$_2$ at low temperatures. In this paper, we report low-energy electronic structure and Fermi surface topology of MoTe$_2$ using angle-resolved photoemission spectrometry (ARPES) technique and first-principle calculations, and compare them with that of WTe$_2$ to understand the mechanism of XMR. Our measurements demonstrate that MoTe$_2$ is an uncompensated semimetal, contrary to WTe$_2$ in which compensated electron-hole pockets have been identified, ruling out the applicability of charge compensation theory for the nonsaturating XMR in MoTe$_2$. In this context, we also discuss the applicability of the existing other conjectures on the XMR of these compounds.
Large unsaturated magnetoresistance (XMR) with magnitude about 1000% is observed in topological insulator candidate TaSe3 from our high field (up to 38 T) measurements. Two oscillation modes, associated with one hole pocket and two electron pockets in the bulk, respectively, are detected from our Shubnikov-de Hass (SdH) measurements, consistent with our first-principles calculations. With the detailed Hall measurements performed, our two-band model analysis exhibits an imperfect density ratio n_h/n_e closing 0.9 at T< 20 K , which suggests that the carrier compensations account for the XMR in TaSe3.
We report the magneto-transport properties and the electronic structure of TmSb. TmSb exhibits extremely large transverse magnetoresistance and Shubnikov-de Haas (SdH) oscillation at low temperature and high magnetic field. Interestingly, the split of Fermi surfaces induced by the nonsymmetric spin-orbit interaction has been observed from SdH oscillation. The analysis of the angle-dependent SdH oscillation illustrates the contribution of each Fermi surface to the conductivity. The electronic structure revealed by angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations demonstrates a gap at $X$ point and the absence of band inversion. Combined with the trivial Berry phase extracted from SdH oscillation and the nearly equal concentrations of electron and hole from Hall measurements, it is suggested that TmSb is a topologically trivial semimetal and the observed XMR originates from the electron-hole compensation and high mobility.
Electron-hole (e-h) compensation is a hallmark of multi-band semimetals with extremely large magnetoresistance (XMR) and has been considered to be the basis for XMR. Recent spectroscopic experiments, however, reveal that YSb with non-saturating magnetoresistance is uncompensated, questioning the e-h compensation scenario for XMR. Here we demonstrate with magnetoresistivity and angle dependent Shubnikov - de Haas (SdH) quantum oscillation measurements that YSb does have nearly perfect e-h compensation, with a density ratio of $0.95$ for electrons and holes. The density and mobility anisotropy of the charge carriers revealed in the SdH experiments allow us to quantitatively describe the magnetoresistance with an anisotropic multi-band model that includes contributions from all Fermi pockets. We elucidate the role of compensated multi-bands in the occurrence of XMR by demonstrating the evolution of calculated magnetoresistances for a single band and for various combinations of electron and hole Fermi pockets.
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) Dirac bands at the M and R points. Because the small m* and the large carrier mobilities will be realized, these hidden 3D Dirac bands should play an important role for the XMR in InBi. We suggest that this feature can be employed as a novel strategy for the creation of XMR semimetals.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
