Discovery of intertwined pair density and charge density wave orders in UTe2

TL;DR

This study reveals intertwined charge density wave orders and potential pair density wave states in UTe2, showing how magnetic fields and temperature influence these electronic orders, advancing understanding of unconventional superconductivity.

Contribution

The paper provides direct evidence of pair density wave and related charge orders in UTe2, linking their behavior to magnetic field and temperature, which was previously unestablished.

Findings

Identification of nondispersive CDW modulations with distinct temperature and field dependencies.

Observation that certain CDW peaks vanish near Tc while others persist above Tc.

Correlation between critical fields of CDW peaks and anisotropic Hc2, suggesting PDW presence above Tc.

Abstract

The strongly correlated spin-triplet superconductor UTe2 hosts an unusual landscape of magnetic-field-sensitive charge density wave (CDW) phases, positioning it as a compelling system for studying intertwined electronic orders. A central challenge is determining whether the observed charge modulations arise from a triplet pair density wave (PDW) order and, if so, how the anisotropic magnetic field response of triplet superconductivity is manifested in the CDW response. Here, using a scanning tunneling microscope equipped with a vector magnetic field, we systematically investigate the evolution and interrelation of distinct CDW orders. Complementing the previously identified incommensurate CDW peaks (qi=1,2,3), we resolve an additional set of nondispersive modulations (pi=1,2,3 and h1,2) with distinct temperature and magnetic field dependencies. The pi CDW peaks vanish near Tc, while the qi peaks survive well above Tc but are progressively suppressed by magnetic field in an anisotropic manner. The critical fields of the qi peaks mirror the directional hierarchy of Hc2, which suggests a PDW is present above the bulk Tc. This is consistent with a Landau free-energy picture where PDWs with wavevectors pi form above the bulk Tc, leading to composite CDW orders with wavevector qi. Below Tc, the coupling of PDWs and uniform superconductivity leads to the pi CDWs. Together, these findings establish UTe2 as a rare platform where both the parent PDW and descendant orders are directly resolved, enabling access to both the fundamental and emergent manifestations of PDW physics.