Observation of cyclotron resonance and measurement of the hole mass in optimally doped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>La</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>Sr</mml:mi></mml:mrow><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mrow><mml:mi>CuO</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:math>
K. W. Post, Anaëlle Legros, D.G. Rickel, John Singleton, R. McDonald, Xi He, I. Božović, Xiaotao Xu, Xiaoyan Shi, N. P. Armitage, S. A. Crooker
Abstract
Using time-domain terahertz spectroscopy in pulsed magnetic fields up to 31 T, we measure the terahertz optical conductivity in an optimally doped thin film of the high-temperature superconducting cuprate ${\mathrm{La}}_{1.84}{\mathrm{Sr}}_{0.16}{\mathrm{CuO}}_{4}$. We observe systematic changes in the circularly polarized complex optical conductivity that are consistent with cyclotron absorption of $p$-type charge carriers characterized by a cyclotron mass of $4.9{m}_{\mathrm{e}}\ifmmode\pm\else\textpm\fi{}0.8{m}_{\mathrm{e}}$ and a scattering rate that increases with magnetic field. These results open the door to studies aimed at characterizing the degree to which electron-electron interactions influence carrier masses in cuprate superconductors.