_version_ 1866913838448771072
author Hasan, Zubia
Pan, Grace A.
LaBollita, Harrison
Kaczmarek, Austin
Sung, Suk Hyun
Sharma, Shekhar
Balakrishnan, Purnima P.
Mercer, Edward
Bhartiya, Vivek
Salman, Zaher
Prokscha, Thomas
Suter, Andreas
Grutter, Alexander J.
Garcia-Fernandez, Mirian
Zhou, Ke-Jin
Pelliciari, Jonathan
Bisogni, Valentina
Baggari, Ismail El
Schlom, Darrell G.
Barone, Matthew R.
Brooks, Charles M.
Nowack, Katja C.
Botana, Antia S.
Faeth, Brendan D.
de la Torre, Alberto
Mundy, Julia A.
author_facet Hasan, Zubia
Pan, Grace A.
LaBollita, Harrison
Kaczmarek, Austin
Sung, Suk Hyun
Sharma, Shekhar
Balakrishnan, Purnima P.
Mercer, Edward
Bhartiya, Vivek
Salman, Zaher
Prokscha, Thomas
Suter, Andreas
Grutter, Alexander J.
Garcia-Fernandez, Mirian
Zhou, Ke-Jin
Pelliciari, Jonathan
Bisogni, Valentina
Baggari, Ismail El
Schlom, Darrell G.
Barone, Matthew R.
Brooks, Charles M.
Nowack, Katja C.
Botana, Antia S.
Faeth, Brendan D.
de la Torre, Alberto
Mundy, Julia A.
contents Geometrically frustrated lattices can display a range of correlated phenomena, ranging from spin frustration and charge order to dispersionless flat bands due to quantum interference. One particularly compelling family of such materials is the half-valence spinel Li$B_2$O$_4$ materials. On the $B$-site frustrated pyrochlore sublattice, the interplay of correlated metallic behavior and charge frustration leads to a superconducting state in LiTi$_2$O$_4$ and heavy fermion behavior in LiV$_2$O$_4$. To date, however, LiTi$_2$O$_4$ has primarily been understood as a conventional BCS superconductor despite a lattice structure that could host more exotic groundstates. Here, we present a multimodal investigation of LiTi$_2$O$_4$, combining ARPES, RIXS, proximate magnetic probes, and ab-initio many-body theoretical calculations. Our data reveals a novel mobile polaronic ground state with spectroscopic signatures that underlie co-dominant electron-phonon coupling and electron-electron correlations also found in the lightly doped cuprates. The cooperation between the two interaction scales distinguishes LiTi$_2$O$_4$ from other superconducting titanates, suggesting an unconventional origin to superconductivity in LiTi$_2$O$_4$. Our work deepens our understanding of the rare interplay of electron-electron correlations and electron-phonon coupling in unconventional superconducting systems. In particular, our work identifies the geometrically frustrated, mixed-valence spinel family as an under-explored platform for discovering unconventional, correlated ground states.
format Preprint
id arxiv_https___arxiv_org_abs_2505_09762
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unconventional polaronic ground state in superconducting LiTi$_2$O$_4$
Hasan, Zubia
Pan, Grace A.
LaBollita, Harrison
Kaczmarek, Austin
Sung, Suk Hyun
Sharma, Shekhar
Balakrishnan, Purnima P.
Mercer, Edward
Bhartiya, Vivek
Salman, Zaher
Prokscha, Thomas
Suter, Andreas
Grutter, Alexander J.
Garcia-Fernandez, Mirian
Zhou, Ke-Jin
Pelliciari, Jonathan
Bisogni, Valentina
Baggari, Ismail El
Schlom, Darrell G.
Barone, Matthew R.
Brooks, Charles M.
Nowack, Katja C.
Botana, Antia S.
Faeth, Brendan D.
de la Torre, Alberto
Mundy, Julia A.
Superconductivity
Strongly Correlated Electrons
Geometrically frustrated lattices can display a range of correlated phenomena, ranging from spin frustration and charge order to dispersionless flat bands due to quantum interference. One particularly compelling family of such materials is the half-valence spinel Li$B_2$O$_4$ materials. On the $B$-site frustrated pyrochlore sublattice, the interplay of correlated metallic behavior and charge frustration leads to a superconducting state in LiTi$_2$O$_4$ and heavy fermion behavior in LiV$_2$O$_4$. To date, however, LiTi$_2$O$_4$ has primarily been understood as a conventional BCS superconductor despite a lattice structure that could host more exotic groundstates. Here, we present a multimodal investigation of LiTi$_2$O$_4$, combining ARPES, RIXS, proximate magnetic probes, and ab-initio many-body theoretical calculations. Our data reveals a novel mobile polaronic ground state with spectroscopic signatures that underlie co-dominant electron-phonon coupling and electron-electron correlations also found in the lightly doped cuprates. The cooperation between the two interaction scales distinguishes LiTi$_2$O$_4$ from other superconducting titanates, suggesting an unconventional origin to superconductivity in LiTi$_2$O$_4$. Our work deepens our understanding of the rare interplay of electron-electron correlations and electron-phonon coupling in unconventional superconducting systems. In particular, our work identifies the geometrically frustrated, mixed-valence spinel family as an under-explored platform for discovering unconventional, correlated ground states.
title Unconventional polaronic ground state in superconducting LiTi$_2$O$_4$
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2505.09762