Large magnetoresistance in topological insulator candidate TaSe3

Abstract

Large unsaturated magnetoresistance (XMR) with magnitude ∼10 3 % is observed in topological insulator candidate TaSe 3 from our high field (up to 38 T) measurements.Two oscillation modes are detected associated with the bulk pockets from our Shubnikov-de Hass (SdH) measurements, consistent with our first-principles calculations. However, our SdH measurements fails to determine the existence of topological surface states in TaSe 3 , calling for more powerful means to detect on this compound. Moreover, our two-band model analysis exhibits that an imperfect density ratio / ≈ 0.9 accounts for XMR at T< 20 K. At T> 20 K, a sudden change of density of carriers suggests a reconstruction of the Fermi surface. Thus, TaSe 3 may provide an opportunity to allow us to observe XMR in a topological insulator and to exploit the potential interplay between the XMR and topological surface states for the first time.

Electrically Insulating Flexible Films with Quasi‐1D van der Waals Fillers as Efficient Electromagnetic Shields in the GHz and Sub‐THz Frequency Bands

“…1c), and quantitative EDS averaged across the entire mapped area (SI) provides a slightly Se-deficient composition of TaSe2.85 similar to other samples prepared by CVT. [6,34] Powder x-ray diffraction (XRD) is consistent with the anticipated monoclinic TaSe3 structure, and it confirms the phase purity of the as-prepared material (Fig. 1d).…”

“…The fact that this material revealed extremely high current densities when exfoliated into the bundles of atomic threads was an additional important factor. [ 6 ] Recent interest in TaSe 3 has included studies of its topological phases, [ 17,32–34 ] the effect of strain on its metallic versus semiconducting states, [ 35 ] low temperature charge density wave (CDW) states, [ 18 ] and our own work characterizing its current carrying capacity and low‐frequency electronic noise. [ 36 ] The room temperature, monoclinic crystal structure of TaSe 3 ( Figure a) exhibits aligned chains of trigonal prismatic [TaSe 6 ] units oriented along the b ‐axis.…”

“…The spectrum displays characteristic peaks between 25 cm -1 to 300 cm -1 , which originate from the primitive monoclinic structure of TaSe3. [18,34,35] The peaks at 140 cm -1 , 164 cm -1 , 214 cm -1 and 238 cm -1 are assigned to the out-ofplane A1g phonon modes whereas the peaks at 176 cm -1 and 185 cm -1 to the B2/Ag modes. [35] The Raman data confirm the crystalline nature of the TaSe3 filler and the preservation of its structural integrity after all processing steps.…”

Observation of Topological Electronic Structure in Quasi-1D Superconductor TaSe3

“…Two main peaks with frequencies of F 1 = 84 G 8 T and F 2 = 180 G 9 T were deduced Article by fast Fourier transformation (FFT) (see Supplemental Experimental Procedures, part II), indicating the existence of two Fermi surface (FS) pockets with area of 0.008 G 0.001 A ˚À2 and 0.017 G 0.001 A ˚À2 , in line with recent reports. 41,42 Since the prismatic Ta-Se chains have strong bonding along the a and b axes but relatively weak bonding along the c axis, the compound is easily cleaved along the ½101 direction, as previously illustrated in Figure 1B. The morphology of the cleaved surface was investigated by STM measurement.…”

“…In addition, in the monolayer limit, 39 a quantum spin Hall insulator phase is expected so that the topological edge state is expected to form a 1D TSC (see Supplemental Experimental Procedures part I, and Guille ´n et al 40 ). Furthermore, TaSe 3 contains many other intriguing physical properties such as large non-saturating magneto-resistance, 41,42 charge density wave in mesowires, 43 high current-carrying capacity, 44,45 and low levels of noise spectral density, 46 making it an important platform from which to study the nature of TSCs as well as possible applications such as interconnects in quantum computers. 44,45 Despite the strong motivations, the experimental confirmation of the topological electronic structure of TaSe 3 is challenging.…”