Single crystal growth and transport properties of narrow-bandgap semiconductor RhP2

Abstract

Abstract We report the growth of high-quality single crystals of RhP2, and systematically study its structure and physical properties by transport, magnetism, and heat capacity measurements. Single-crystal x-ray diffraction reveals that RhP2 adopts a monoclinic structure with the cell parameters a = 5.7347(10) Å, b = 5.7804(11) Å, and c = 5.8222(11) Å, space group P21/c (No. 14). The electrical resistivity ρ(T) measurements indicate that RhP2 exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions, respectively. The temperature-dependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration. We find that RhP2 has a high mobility μ e ∼ 210 cm2⋅V−1⋅s−1 with carrier concentrations n e ∼ 3.3 × 1018 cm−3 at 300 K with a narrow-bandgap feature. The high mobility μ e reaches the maximum of approximately 340 cm2⋅V−1⋅s−1 with carrier concentrations n e ∼ 2 × 1018 cm−3 at 100 K. No magnetic phase transitions are observed from the susceptibility χ(T) and specific heat C p(T) measurements of RhP2. Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.