Pressure Tuning of the Charge Density Wave in the Halogen-Bridged Transition-Metal (MX) Solid $Pt_2Br_6(NH_3)_4$

TL;DR

This study investigates how applying pressure affects the charge density wave in a quasi-one-dimensional transition-metal halogen compound, revealing a transition to a different broken-symmetry state rather than metallization.

Contribution

It demonstrates that pressure induces a transition in the charge density wave state of $Pt_2Br_6(NH_3)_4$, modeled effectively with a Peierls-Hubbard Hamiltonian, challenging previous predictions of insulator-to-metal transition.

Findings

No pressure-induced insulator-to-metal transition observed.

Evidence suggests a transition to a different broken-symmetry ground state.

Modeling aligns with a Peierls-Hubbard Hamiltonian approach.

Abstract

We report the pressure dependence up to 95 kbar of Raman active stretching modes in the quasi-one-dimensional MX chain solid $Pt_2Br_6(NH_3)_4$. The data indicate that a predicted pressure-induced insulator-to-metal transition does not occur, but are consistent with the solid undergoing either a three-dimensional structural distortion, or a transition from a charge-density wave to another broken-symmetry ground state. We show that such a transition cacan be well-modeled within a Peierls-Hubbard Hamiltonian. 1993 PACS: 71.30.+h, 71.45.Lr, 75.30.Fv, 78.30.-j, 81.40.Vw