Observation of giant circular dichroism induced by electronic chirality

Abstract

Chiral phases of matter, characterized by a definite handedness, abound in nature, ranging from the crystal structure of quartz to spiraling spin states in helical magnets. In $1T$-TiSe${}_2$ a source of chirality has been proposed that stands apart from these classical examples as it arises from combined electronic charge and quantum orbital fluctuations. This may allow its chirality to be accessed and manipulated without imposing either structural or magnetic handedness. However, direct bulk evidence that broken inversion symmetry and chirality are intrinsic to TiSe${}_2$ remains elusive. Here, employing resonant elastic scattering of x-rays, we reveal the presence of giant circular dichroism up to $\sim$ 40$\%$ at forbidden Bragg peaks that emerge at the charge and orbital ordering transition. The dichroism varies dramatically with incident energy and azimuthal angle. Comparison to calculated scattering intensities unambiguously traces its origin to bulk chiral electronic order in ${\mathrm{TiSe}}_2$ and establishes resonant elastic x-ray scattering as a sensitive probe to electronic chirality.

6 pages, 4 figures

References in corpus (7)

• Time-reversal symmetry-breaking charge order in a kagome superconductor
• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Controlling many-body states by the electric-field effect in a two-dimensional material
• Chiral flux phase in the Kagome superconductor AV${}_3$Sb${}_5$
• Optical detection and manipulation of spontaneous gyrotropic electronic order in a transition-metal dichalcogenide semimetal
• Effect of Cu intercalation and pressure on excitonic interaction in 1T-TiSe2
• Observation of orbital order in the Van der Waals material 1T-TiSe2

Cited by in corpus (4)

• Photo-induced Dynamics and Momentum Distribution of Chiral Charge Density Waves in 1T-TiSe${}_2$
• Non-chiral 1T-TiSe2 creates circular dichroism in resonant X-ray diffraction via multipole scattering interference
• Doping-induced nematic and stripe orders within the charge density wave state of TiSe${}_2$
• Revisiting the charge-density-wave superlattice of 1$T$-TiSe${}_2$