Molecular beam epitaxy growth of nonmagnetic Weyl semimetal LaAlGe thin film

Abstract

Here, the authors report a detailed method of growing LaAlGe, a nonmagnetic Weyl semimetal, thin film on silicon(100) substrates by molecular beam epitaxy and their structural and electrical characterizations. About 50-nm-thick LaAlGe films were deposited and annealed for 16 h in situ at a temperature of 793 K. As-grown high-quality films showed uniform surface topography and near ideal stoichiometry with a body-centered tetragonal crystal structure. Temperature-dependent longitudinal resistivity can be understood with dominant interband s-d electron-phonon scattering in the temperature range of 5-40 K. Hall measurements confirmed the semimetallic nature of the films with an electron-dominated charge carrier density of ∼7.15 × 10 21 cm −3 at 5 K.

High Fermi velocities and small cyclotron masses in LaAlGe

“…H is the slope of ρ xy [Fig.1(d,e)]. Carrier concentration shows reduction above 40 K and is consistent with result obtained in thin films 30. This is coincident with increased resistivity [Fig.1(b)] above 40 K, indicating that ρ(T ) is also influenced by changes in n, in addition to phonon-related scattering induced by increased…”

“…[23][24][25][26] LaAlGe features type-II Weyl nodes. [27][28][29] Thin films of LaAlGe show metallic resistivity, small residual resistivity ratio RRR = ρ(300 K)/ρ (5 K) = 1.17, relatively high residual resistivity of about 87 µΩ cm, single band electronic transport and 7×10 21 cm −2 carrier concentration at 5 K. 30 In particular, contribution of Weyl points at the Fermi surface, dimensionality and characteristics of such states are important. Here we perform quantum oscillation studies of LaAlGe.…”

Magnetotransport Study of Dirac Metal FeSn Thin Films Grown on Silicon Substrates

“…[9,12] Hall resistivity, ρ xy , measurements were taken at various temperatures starting from room temperature (300 K) down to 5 K and in a magnetic field up to AE4 T. Studies have shown that taking Hall measurements in positive as well as negative field directions helps to improve the precision of data. [18] Separate devices of 30 and 50 nm thick FeSn grown on different substrates were used for the Hall measurements. Figure 8 displays the ρ xy measured for the 30 nm thick FeSn device on Si(100).…”

Crystalline materials for quantum computing: Semiconductor heterostructures and topological insulators exemplars

“…Materials grown by conventional epitaxy include Cd 3 As 2 , NbP, TaP, Na 3 Bi, Sr 3 PbO, LaAlGe, Co 3 Sn 2 S 2 , and TaIrTe 4 . [83][84][85][86][87][88][89][90][91] In most of these cases, the more volatile element (i.e., As, P, S, Te) is held in excess, while the less volatile element controls the growth rate. However, in the cases of materials like LaAlGe or Na 3 Bi, more careful flux matching is needed.…”