High precision measurement of the Dzyaloshinsky-Moriya interaction between two rare-earth ions in a solid

TL;DR

This paper presents a novel broadband ESR technique with optical detection to directly measure and fully characterize the Dzyaloshinsky-Moriya interaction between two rare-earth ions in a solid, with implications for magnetic phenomena and quantum computing.

Contribution

Introduces a new method to precisely measure the Dzyaloshinsky-Moriya interaction and determine the full spin-spin coupling tensor in a solid-state system.

Findings

Successfully measured the DMI strength and direction in Nd3+-doped YVO4.

Detected a singlet-triplet transition with suppressed magnetic-field dependence.

Demonstrated potential for long-coherence quantum bits using singlet-triplet states.

Abstract

We report on a direct measurement of the pair-wise anti-symmetric exchange interaction, known as the Dzyaloshinsky-Moriya interaction (DMI), in a Nd3+-doped YVO4 crystal. To this end we introduce a broadband electron spin resonance technique coupled with an optical detection scheme which selectively detects only one Nd3+-Nd3+ pair. Using this technique we can fully determine the spin-spin coupling tensor, allowing us to experimentally determine both the strength and direction of the DMI vector. We believe that this ability to fully determine the interaction Hamiltonian is of interest for studying the numerous magnetic phenomena where the DMI interaction is of fundamental importance, including multiferroics. We also detect a singlet-triplet transition within the pair, with a highly suppressed magnetic-field dependence, which suggests that such systems could form singlet-triplet qubits with long coherence times for quantum information applications.