Direct probing of temperature-independent bulk half-metallicity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Co</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi>MnSi</mml:mi></mml:mrow></mml:math> by spin-resolved hard x-ray photoemission

We have performed the bulk-sensitive spin-resolved hard x-ray photoelectron spectroscopy (HAXPES) to directly clarify spin-dependent valence band electronic states and spin polarization of $L{2}_{1}$-ordered ${\mathrm{Co}}_{2}\mathrm{MnSi}$ as a predicted half-metal. The HAXPES spectra clearly exhibited difference in majority minority bulk region 30-nm-thick ${\mathrm{Co}}_{2}\mathrm{MnSi}(001)$ thin film buried under MgO(2 nm) layer at both temperatures 21 300 K. As expected from half-metallicity ${\mathrm{Co}}_{2}\mathrm{MnSi}$, we found that (minority) spectrum shows metallic Fermi edge (a gap), leading high \ensuremath{\sim}90% around level temperature experiments revealed is independent on up also slight changes spectral shapes shift maximum with temperature. By comparing experimental results first-principles calculations finite obtained by disordered local moment method, it suggested mainly caused temperature-dependent Co $3d$ states. It conduction minimum located sufficiently above