paper

Robust narrow-gap semiconducting behavior in square-net La $_{3}$ Cd $_{2}$ As $_{6}$

arXiv:2108.08006 · doi:10.1021/acs.chemmater.1c00797

Abstract

ABSTRACT: Narrow-gap semiconductors are sought-after materials due to their potential for long-wavelength detectors, thermoelectrics, and more recently non-trivial topology. Here we report the synthesis and characterization of a new family of narrow-gap semiconductors, $R$ $_{3}$ Cd $_{2}$ As $_{6}$ ( $R =$ La, Ce). Single crystal x-ray diffraction at room temperature reveals that the As square nets distort and Cd vacancies order in a monoclinic superstructure. A putative charge-density ordered state sets in at 279~K in La $_{3}$ Cd $_{2}$ As $_{6}$ and at 136~K in Ce $_{3}$ Cd $_{2}$ As $_{6}$ and is accompanied by a substantial increase in the electrical resistivity in both compounds. The resistivity of the La member increases by thirteen orders of magnitude on cooling, which points to a remarkably clean semiconducting ground state. Our results suggest that light square net materials within a $I 4/ mmm$ parent structure are promising clean narrow-gap semiconductors.

Robust narrow-gap semiconducting behavior in square-net La3​Cd2​As6​

Abstract

Robust narrow-gap semiconducting behavior in square-net La $_{3}$ Cd $_{2}$ As $_{6}$