Mobility spectrum analytical approach for intrinsic band picture of Ba(FeAs)₂

Abstract

Unconventional high temperature superconductivity as well as three-dimensional bulk Dirac cone quantum states arising from the unique d-orbital topology have comprised an intriguing research area in physics. Here we apply a special analytical approach using a mobility spectrum, in which the carrier number is conveniently described as a function of mobility without any hypothesis, both on the types and the numbers of carriers, for the interpretations of longitudinal and transverse electric transport of high quality single crystal Ba(FeAs) 2 in a wide range of magnetic fields. We show that the majority carriers are accommodated in large parabolic hole and electron pockets with very different topology as well as remarkably different mobility spectra, whereas the minority carriers reside in Dirac quantum states with the largest mobility as high as 70,000 cm 2 (Vs) −1 . The deduced mobility spectra are discussed and compared to the reported sophisticated first principle band calculations.

Transport property of multi-band topological material PtBi$$_2$$ studied by maximum entropy mobility spectrum analysis (MEMSA)

“…2 . It is clear that comparing previous methods 25 , 27 , our MEMSA method perfectly fits the experimental data of conductivity and Hall conductivity spontaneously. The resolution is greatly improved, resulting in well separation of peaks on the MS curve.…”

“…A straightforward way is hypothesizing both carrier types and number of bands, then, calculating mobility and concentration via fitting 18 – 20 . In order to avoid the hypothesis, the technique of mobility spectrum (MS), which was initially developed to study carriers in semiconductors 21 – 24 , was applied to Ba(FeAs) 25 and FeSe 26 . The MS resulting from longitudinal and transverse transport under a wide range of magnetic field B up to 50 T, shows a physically reasonable and intrinsic interpretation on the electronic states in low temperature phase.…”

Electric transport of a single-crystal iron chalcogenide FeSe superconductor: Evidence of symmetry-breakdown nematicity and additional ultrafast Dirac cone-like carriers

“…In this letter, we report on the detailed electronic structure of a FeSe bulk single crystal studied by transport measurements under magnetic fields. The experimental data, by employing ab initio mobility spectrum analysis without making assumptions on the carrier numbers successfully applied to Ba(FeAs) 2 in our previous study [20], clearly demonstrate that the electron and the hole pockets with almost equivalent carrier numbers of ∼10 20 cm −3 are present in the majority of carrier bands, which is consistent with a carrier-compensated semimetallic feature. In addition, we intriguingly find that another minority band with the carrier number of ∼10 18 cm −3 is also present.…”

Itinerant antiferromagnetic BaMn$_2$Pn$_2$'s showing both negative and positive magnetoresistances

“…1(d) we compare the low-temperature magnetotransport properties between BMAs and and its sister compound BaFe 2 As 2 . Magnetotransport properties of BaFe 2 As 2 , which is a compensated multiband semimetal with tiny Dirac cone states 27,28 , generally obey the law of semiclassical transport theory. In particular, magnetoresistance (MR), defined as MR = ρ(H)/ρ(0) − 1 where ρ is the resistivity, is minimized when H is aligned parallel to the current density (j) and monotonically and gradually increases with H 226 .…”