Control of band structure of FeSe single crystals via biaxial strain
M. Nakajima,
Y. Ohata,
S. Tajima
Abstract:We performed systematic transport measurements on FeSe single crystals with applying in-plane biaxial strain ε ranging from −0.96% to 0.23%. Biaxial strain was introduced by firmly gluing samples to various substrate materials with different thermal expansion. With increasing ε, structural and superconducting transition temperatures monotonically increased and decreased, respectively. We analyzed magneto-transport results using a compensated three-carrier model. The evaluated densities of hole and electron car… Show more
“…The reduction of the coherent carrier density induced by the nematic transition should affect superconductivity. In the present system, the carrier density seems to correlate with T c [11,12,49]. In this context, the presence of the nematic transition, which reduces the coherent carrier density, hinders superconductivity, although it is not clear whether the presence of the nematic order itself competes with superconductivity.…”
Section: Effect Of the Nematic Transitionmentioning
confidence: 61%
“…The nematic transition in FeSe can be tuned by chemical substitution [7,8], hydrostatic pressure [9,10], and in-plane biaxial strain [11,12]. To study the influence of electronic nematicity on superconductivity, isovalent S substitution and physical pressure have been employed so far, but this is not straightforward to understand the * nakajima@phys.sci.osaka-u.ac.jp electronic state because magnetism is simultaneously involved [13][14][15][16].…”
We systematically studied in-plane optical conductivity of FeSe1−xTex thin films fabricated on CaF2 substrates for x = 0, 0.1, 0.2, and 0.4. This system shows a large enhancement of superconducting transition temperature Tc at x ∼ 0.2 and a gentle decrease in Tc with further increasing x. The low-energy optical conductivity spectrum is described by the sum of narrow and broad Drude components, associated with coherent and incoherent charge dynamics, respectively. With increasing Te content, the spectral weight of the narrow Drude component decreases, while the total weight of the two Drude components increases. As a consequence, the fraction of the narrow Drude weight significantly decreases, indicating that Te substitution leads to stronger electronic correlations. Below the nematic transition temperature, the narrow Drude weight decreases with decreasing temperature. This indicates the reduction of the coherent carrier density, resulting from the Fermi-surface modification induced by the development of the orbital order. The reduction of the narrow Drude weight with temperature stopped at x ∼ 0.2, corresponding to the disappearance of the nematic transition. Our result suggests that the increase in the coherent carrier density induced by the suppression of the nematic transition gives rise to the enhancement of Tc. The decrease in Tc with further Te substitution likely arises from too strong electronic correlations, which are not favorable for superconductivity.
“…The reduction of the coherent carrier density induced by the nematic transition should affect superconductivity. In the present system, the carrier density seems to correlate with T c [11,12,49]. In this context, the presence of the nematic transition, which reduces the coherent carrier density, hinders superconductivity, although it is not clear whether the presence of the nematic order itself competes with superconductivity.…”
Section: Effect Of the Nematic Transitionmentioning
confidence: 61%
“…The nematic transition in FeSe can be tuned by chemical substitution [7,8], hydrostatic pressure [9,10], and in-plane biaxial strain [11,12]. To study the influence of electronic nematicity on superconductivity, isovalent S substitution and physical pressure have been employed so far, but this is not straightforward to understand the * nakajima@phys.sci.osaka-u.ac.jp electronic state because magnetism is simultaneously involved [13][14][15][16].…”
We systematically studied in-plane optical conductivity of FeSe1−xTex thin films fabricated on CaF2 substrates for x = 0, 0.1, 0.2, and 0.4. This system shows a large enhancement of superconducting transition temperature Tc at x ∼ 0.2 and a gentle decrease in Tc with further increasing x. The low-energy optical conductivity spectrum is described by the sum of narrow and broad Drude components, associated with coherent and incoherent charge dynamics, respectively. With increasing Te content, the spectral weight of the narrow Drude component decreases, while the total weight of the two Drude components increases. As a consequence, the fraction of the narrow Drude weight significantly decreases, indicating that Te substitution leads to stronger electronic correlations. Below the nematic transition temperature, the narrow Drude weight decreases with decreasing temperature. This indicates the reduction of the coherent carrier density, resulting from the Fermi-surface modification induced by the development of the orbital order. The reduction of the narrow Drude weight with temperature stopped at x ∼ 0.2, corresponding to the disappearance of the nematic transition. Our result suggests that the increase in the coherent carrier density induced by the suppression of the nematic transition gives rise to the enhancement of Tc. The decrease in Tc with further Te substitution likely arises from too strong electronic correlations, which are not favorable for superconductivity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.