Frustration-driven correlated parent states in the spinel superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>LiTi</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">O</m

Geometrically frustrated transition-metal oxides provide fertile ground for the emergence of novel quantum states. In the spinel superconductor <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:msub> <a:mi>LiTi</a:mi> <a:mn>2</a:mn> </a:msub> <a:msub> <a:mi mathvariant="normal">O</a:mi> <a:mn>4</a:mn> </a:msub> </a:mrow> </a:math> (superconducting critical temperature <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mrow> <c:msub> <c:mi>T</c:mi> <c:mi mathvariant="normal">c</c:mi> </c:msub> <c:mo>≈</c:mo> <c:mn>13</c:mn> <c:mspace width="0.16em"/> <c:mi mathvariant="normal">K</c:mi> </c:mrow> </c:math> , formal <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"> <g:mrow> <g:mn>3</g:mn> <g:msup> <g:mrow> <g:mi>d</g:mi> </g:mrow> <g:mrow> <g:mn>0.5</g:mn> </g:mrow> </g:msup> </g:mrow> </g:math> system), we uncover a prominent dispersion kink near the Fermi energy accompanied by negative thermal expansion below a characteristic temperature <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:mrow> <h:msup> <h:mi>T</h:mi> <h:mo>*</h:mo> </h:msup> <h:mo>≈</h:mo> <h:mn>150</h:mn> <h:mspace width="0.16em"/> <h:mi mathvariant="normal">K</h:mi> </h:mrow> </h:math> . We propose that charge frustration in the pyrochlore lattice leads to a degenerate electronic arrangement on <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"> <k:mrow> <k:mi mathvariant="normal">T</k:mi> <k:msup> <k:mrow> <k:mi mathvariant="normal">i</k:mi> </k:mrow> <k:mrow> <k:mn>3</k:mn> <k:mo>+</k:mo> </k:mrow> </k:msup> <k:mo>/</k:mo> <k:mi mathvariant="normal">T</k:mi> <k:msup> <k:mrow> <k:mi mathvariant="normal">i</k:mi> </k:mrow> <k:mrow> <k:mn>4</k:mn> <k:mo>+</k:mo> </k:mrow> </k:msup> </k:mrow> </k:math> sites, giving rise to strong intersite Coulomb interactions below <p:math xmlns:p="http://www.w3.org/1998/Math/MathML"> <p:msup> <p:mi>T</p:mi> <p:mo>*</p:mo> </p:msup> </p:math> . Within this framework, negative thermal expansion arises from the Coulomb repulsion of <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"> <q:mrow> <q:mn>3</q:mn> <q:msup> <q:mrow> <q:mi>d</q:mi> </q:mrow> <q:mn>1</q:mn> </q:msup> </q:mrow> </q:math> electrons, while the prominent kink reflects reduced screening due to enhanced correlations. These findings open up promising avenues for exploring exotic correlated states in frustrated pyrochlore lattices, which are situated near the <r:math xmlns:r="http://www.w3.org/1998/Math/MathML"> <r:mrow> <r:mn>3</r:mn> <r:msup> <r:mrow> <r:mi>d</r:mi> </r:mrow> <r:mn>1</r:mn> </r:msup> </r:mrow> </r:math> Mott state.