Discovery of smectic charge and pair-density-wave orders in topological monolayer 1T$^\prime$-MoTe$_2$

TL;DR

This study uncovers smectic charge and pair-density-wave orders in topological monolayer 1T'–MoTe2 using cryogenic STM, revealing their interplay with superconductivity and underlying electronic nesting behaviors.

Contribution

It is the first to identify coexisting smectic charge order and pair-density-wave in monolayer 1T'–MoTe2, linking these orders to topological and electronic properties.

Findings

Discovery of unidirectional smectic charge order and primary PDW in monolayer 1T'–MoTe2.

Observation of two-gap superconductivity below 6.0 K associated with PDW.

Identification of nesting-driven origin of smectic orders through density functional calculations.

Abstract

Electronic liquid-crystal phases are observed in numerous strongly-correlated systems including high-temperature superconductors. However, identifying these exotic phases and understanding their interplay with superconductivity in topological materials remain challenging. Here we employ a cryogenic scanning tunneling microscopy to discover a smectic (stripe) charge order (CO) and a primary pair-density-wave (PDW) in topological monolayer 1T$^\prime$-MoTe$_2$. The two orders are spatially modulated unidirectionally at the same wavevector, but have a marked spatial phase difference of about 2$\pi$/5. Importantly, the primary PDW state features a two-gap superconductivity below the transition temperature of 6.0 K and induces another unique particle-hole-symmetric CO at twice the PDW wavevector. Combining these results and our density functional calculations, we reveal that the two smectic orders are primarily driven by nesting behaviors between electron and hole pockets. Our findings establish monolayer 1T$^\prime$-MoTe$_2$ as a topological paradigm for exploring electronic smecticity, which intertwines with multiple preexisting symmetry-breaking states.