TITLE: Mechanical Control of Charge Density Waves in exfoliated 1T-TaS2
AUTHOR: Rafael Luque Merino, 2D Foundry group, ICMM-CSIC
WHEN: January, 15 - 12PM
WHERE: Salón de Actos, ICMM-CSIC
ABSTRACT: Strain is a powerful tuning knob for correlated low-dimensional materials, enabling control of collective phases such as charge density waves (CDWs). Here we investigate how mechanical strain modifies CDW-driven transport and switching in exfoliated 1T-TaS₂. Using a flexible, device-compatible platform, we apply controlled uniaxial tensile and compressive strain to thin flakes and perform room-temperature electrical transport measurements. Uniaxial strain reversibly shifts the switching threshold voltage and modifies the nearly commensurate-phase resistance. Such strain-dependent resistance changes the Joule heating generated during a voltage sweep, which in turn shifts the voltage required to trigger the transition. This provides a practical route to mechanically gate collective electronic order. Leveraging this effect, we demonstrate a compact strain/displacement sensor with a sharp, threshold-like electrical response.
To access biaxial strain, we exploit the thermal expansion and contraction of polymer substrates from room temperature to cryogenic temperatures. Under biaxial compression we find that the onset temperature for CDW formation increases by tens of kelvin, suggesting that biaxial strain can directly stabilize charge order in 1T-TaS₂. Together, these results highlight strain, both uniaxial and biaxial, as a versatile handles to control CDW formation in low-dimensional materials.
