Towards Floquet Engineering of Ferroelectric Semiconductors via Coherent Multidimensional Spectroscopy

Bismuth telluroiodide (BiTeI) is a prototypical, ferroelectric Rashba semiconductor (FERSC) which possesses a myriad of interesting electronic and optical properties.^{1, 2} Multiple optical transitions throughout the infrared and visible in BiTeI make it a promising material for understanding spin states in Rashba materials. However, the most promising methods for Floquet engineering of spin states in FERSCs are χ⁽²⁾ and χ⁽³⁾ dependent spectroscopies, e.g., sum frequency generation (SFG), pump-probe spectroscopy.^{3, 4} The electronic structure of BiTeI is well studied, making it an ideal candidate for understanding its nonlinear response. Previous experiments reported the relative prevalence of second harmonic (SHG) over third harmonic generation (THG) output from BiTeI with an input fundamental of 0.80 eV. ^{5, 6} To our knowledge, there are no reports regarding frequency dependent SHG and THG output of BiTeI. Here, we use coherent multidimensional spectroscopy to probe the frequency dependence of SHG and THG output of BiTeI and perovskite FERSCs throughout the visible.⁷ Since the Rashba splitting in BiTeI varies as a function of temperature,⁸ multidimensional harmonic generation experiments on these materials are performed at cryogenic (<i>ca.</i> 90 K) and room temperatures (<i>ca. </i>293 K) to probe the effect of temperature on SHG and THG output. These results will have implications on identifying spectroscopies for understanding and controlling the electronic structure of FERSCs.<br/><br/><br/><b>R</b><b>eferences</b><br/>¹K. Ishizaka<i> et al.</i>, Nature Materials <b>10</b> (2011) 521.<br/>²J. S. Lee<i> et al.</i>, Physical Review Letters <b>107</b>, 117401 (2011)<br/>³J. C. Wright, Annual Review of Analytical Chemistry, Vol 10 <b>10</b> (2017) 45.<br/>⁴Y. Kobayashi<i> et al.</i>, Nature Physics <b>19</b> (2023) 171.<br/>⁵P. Padmanabhan<i> et al.</i>, in <i>Conference on Lasers and Electro-Optics (CLEO)</i>San Jose, CA, 2020).<br/>⁶G. Bianca<i> et al.</i>, ACS Applied Materials & Interfaces <b>14</b> (2022) 34963.<br/>⁷D. J. Morrow<i> et al.</i>, Journal of Physical Chemistry Letters <b>11</b> (2020) 6551.<br/>⁸B. Monserrat, and D. Vanderbilt, Physical Review Materials <b>1</b>, 054201 (2017)