Orbital-dependent charge dynamics in MnP revealed by optical study

TL;DR

This study investigates the orbital-dependent charge dynamics in MnP using optical conductivity measurements, revealing two types of charge carriers with distinct behaviors that are influenced by magnetic phases and may relate to superconductivity.

Contribution

It provides the first detailed optical analysis of MnP's charge carriers, linking flat Fermi sheets and magnetic transitions to unconventional superconductivity.

Findings

Two types of charge carriers with different lifetimes identified.

Short-lifetime carriers are gapped in the helimagnetic phase.

Long-lifetime carriers are anisotropic and less affected by magnetic transitions.

Abstract

Unconventional superconductivity often emerges at the border of long-range magnetic orders. Understanding the low-energy charge dynamics may provide crucial information on the formation of superconductivity. Here we report the unpolarized/polarized optical conductivity study of high quality MnP single crystals at ambient pressure. Our data reveal two types of charge carriers with very different lifetimes. In combination with the first-principles calculations, we show that the short-lifetime carriers have flat Fermi sheets which become gapped in the helimagnetic phase, causing a dramatic change in the low-frequency optical spectra, while the long-lifetime carriers are anisotropic three-dimensional like which are little affected by the magnetic transitions and provide major contributions to the transport properties. This orbital-dependent charge dynamics originates from the special crystal structure of MnP and may have an influence on the unconventional superconductivity and its interplay with helimagnetism at high pressures.