Sample dependence of half-integer quantized thermal Hall effect in the Kitaev spin-liquid candidate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>α</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mi>RuCl</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>
Minoru Yamashita, Jun Gouchi, Yoshiya Uwatoko, Nobuyuki Kurita, Hidekazu Tanaka
Abstract
We have investigated the sample dependence of the half-integer thermal Hall effect in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$ under a magnetic field tilted ${45}^{\ensuremath{\circ}}$ from the $c$ axis to the $a$ axis. We find that the sample with the largest longitudinal thermal conductivity ${\ensuremath{\kappa}}_{xx}$ shows the half-integer quantized thermal Hall effect expected in the Kitaev model. On the other hand, the quantized thermal Hall effect was not observed in the samples with smaller ${\ensuremath{\kappa}}_{xx}$. We suggest that suppressing the magnetic scattering effects on the phonon thermal conduction, which broaden the field-induced gap protecting the chiral edge current of the Majorana fermions, is important to observe the quantized thermal Hall effect.