Giant Gruneisen parameter in a superconducting quantum paraelectric

QC 20210720
Superconductivity and ferroelectricity are typically thought of as incompatible because the former needs free carriers, but the latter is usually suppressed by free carriers. This is unless the carrier concentration is sufficiently low to allow for polar distortions and mobile electrons to cooperate. In the case of strontium titanate with low carrier concentration, superconductivity and ferroelectricity have been shown to be correlated via various tuning methods, such as strain. Here, we report theoretically and experimentally evaluated Gruneisen parameters whose divergent giant values under tensile stress indicate that the dominant phonon mode which enhances the superconducting order is the ferroelectric transverse soft phonon mode. This finding puts strong constraints on other phonon modes as the main contributors to the enhanced superconductivity in strained strontium titanate. The methodology shown here can be applied to strain tune and probe properties of other materials with polar distortions including topologically nontrivial ones.

Xu, B.Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. (författare)
Davino, D.Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. (författare)
Mahabir, A.Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. (författare)
Balatsky, AlexanderKTH,Stockholms universitet,Nordiska institutet för teoretisk fysik (Nordita),University of Connecticut, USA,Nordic Institute for Theoretical Physics NORDITA(Swepub:kth)u10tg5ns (författare)
Aschauer, U.Univ Bern, Dept Chem & Biochem, Bern, Switzerland. (författare)
Sochnikov, I.Univ Connecticut, Dept Phys, Storrs, CT 06269 USA.;Univ Connecticut, Inst Mat Sci, Storrs, CT 06269 USA. (författare)
Univ Connecticut, Dept Phys, Storrs, CT 06269 USA.Nordiska institutet för teoretisk fysik (Nordita) (creator_code:org_t)

Ingår i:Physical Review B: American Physical Society (APS)103:212469-99502469-9969

Av författaren/redakt...: Franklin, J.; Xu, B.; Davino, D.; Mahabir, A.; Balatsky, Alexan ...; Aschauer, U.; visa fler...; Sochnikov, I.; visa färre...

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