Transport properties and crystal structure of layered LaSb2

Abstract

LaSb 2 has a layered crystal structure along the c-axis with ∼2% difference between the in-plane orthorombic a and b axes. Here, we report on the thermal conductivity, electrical resistivity, and Seebeck coefficient from 10 to 300 K as well as the magnetoresistance at 10 K. Using the van der Pauw technique on single crystal samples, the in-plane electrical resistivity tensor has been measured and it is found to be isotropic. An anisotropic crystal structure may have isotropic properties, but in the present case, the isotropic nature stems from crystal imperfection. Single crystal X-ray diffraction provides evidence of a mixing of the inplane aand b-directions leading to observed diffraction intensity where systematic absences are expected. Whether the underlying structural mechanism is twinning or stacking faults is unknown, but it could be the origin of the previously observed charge density wave states, and it may also explain the high unsaturating linear magnetoresistance reported here. At ambient conditions, LaSb 2 is found to be stable in air, with no sign of bulk degradation after 5 years of storage; however, some change is observed in the amorphous background scattering.

Pressure-dependent structural and electronic instabilities in LaSb$_2$

“…It is notable that crystals of LaSb 2 grown by flux are predisposed towards twinning [6], which is often an indication that the crystal has been cooled through a structural transition, like in the case in the famous Dauphiné twins of quartz [25]. This is consistent with reports of a distinct, high-temperature form of LaSb 2 [26].…”

“…LaSb 2 , the isostructural, non-magnetic counterpart to CeSb 2 , exhibits superconductivity at ambient pressure [6]. While the magnetoresistance (MR) of a conventional Fermi-liquid metal is expected to scale quadratically with increasing magnetic field, the large MR of LaSb 2 remains linear, without saturating in fields in excess of 45 T [6,7].…”

Anisotropic and High‐Mobility Electronic Transport in a Quasi 2D Antiferromagnet NdSb2

“…[66] We note that this linear MR might be a characteristics of quasi 2D CDW materials [67][68][69] including LaSb 2 . [70,71] Analogous to the transition metal dichalcogenides which also show linear MR, [68,69] variable electron-phonon coupling along with an imperfect Fermi surface nesting, [72] open-orbit Fermi pockets and/or magnetic breakdown in the CDW state [68,69] can be the possible mechanisms that would play an important role in LnSb 2 . The quasiparticle scattering mechanism on the fluctuation of the CDW order parameter near the Fermi surface "hot spots," generated by the imperfect nesting, has also been discussed in context of the linear MR in rare-earth tritellurides.…”

Pressure-induced magnetic phase and structural transition in SmSb2

“…1(a), and we choose SmSb 2 as a representative. A charge density wave (CDW) order has been reported in LaSb 2 and PrSb 2 , [15,16,18] and the former also displays superconductivity below ∼ 1 K. [19][20][21][22] All of RSb 2 except LaSb 2 exhibit an antiferromagnetic (AFM) or a ferromagnetic ground state. [16,19,[23][24][25][26] All RSb 2 materials present large, linear and unsaturated magnetoresistivity (MR) with external magnetic field along c axis, while its origin still remains elusive.…”