Quantum geometry and elliptic optical dichroism in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>p</mml:mi></mml:math>-wave magnets

The quantum geometric tensor is composed of the Berry curvature and the quantum metric, which is observable by means of optical absorption of elliptically polarized light. Especially, the quantum geometric tensor at the zero-momentum is observable by the optical absorption at the optical band edge. In this context, we study optical absorption of a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>p</a:mi></a:math>-wave magnet under irradiation of elliptically polarized light. The <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mi>p</b:mi></b:math>-wave magnet has a band splitting along one axis, which we choose as the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mi>x</c:mi></c:math> axis. We obtain exact analytic formulas for the optical conductivity when the Néel vector is along the <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mi>x</d:mi></d:math>, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:mi>y</e:mi><e:mo>,</e:mo></e:mrow></e:math> and <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mi>z</f:mi></f:math> axis. The optical conductivity strongly depends on the degree of ellipticity of light, which is an elliptic dichroism. Especially, there is a perfect elliptic optical dichroism when the Néel vector is along the <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mi>y</g:mi></g:math> axis. It is possible to determine the Néel vector by measuring the ellipticity of the perfect elliptic dichroism, which will be a key to future magnetic memory based on the <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:mi>p</h:mi></h:math>-wave magnet.