Experimental observation of electron-phonon coupling enhancement in Sn nanowires caused by phonon confinement effects

Lozano, DP; Couet, S; Petermann, C; Hamoir, G; Jochum, JK; Picot, T; Menendez, E; Houben, K; Joly, V; Antohe, VA; Hu, Michael Y; Leu, BM; Alatas, A; Said, Ayman H; Roelants, S; Partoens, B; Milosevic, MV; Peeters, FM; Piraux, L; Van de Vondel, J; Vantomme, A; Temst, K; Van Bael, MJ

doi:10.1103/PhysRevB.99.064512

Experimental observation of electron-phonon coupling enhancement in Sn nanowires caused by phonon confinement effects

Author:

Lozano, DP

Couet, S ; Petermann, C ; Hamoir, G ; Jochum, JK ; Picot, T ; Menendez, E ; Houben, K ; Joly, V ; Antohe, VA ; Hu, Michael Y ; Leu, BM ; Alatas, A ; Said, Ayman H ; Roelants, S ; Partoens, B ; Milosevic, MV ; Peeters, FM ; Piraux, L ; Van de Vondel, J ; Vantomme, A ; Temst, K ; Van Bael, MJ

Keywords:

Science & Technology, Technology, Physical Sciences, Materials Science, Multidisciplinary, Physics, Applied, Physics, Condensed Matter, Materials Science, Physics, SUPERCONDUCTIVITY, SPECTROSCOPY, FABRICATION, ARRAYS, TIN, 02 Physical Sciences, 03 Chemical Sciences, 09 Engineering, Fluids & Plasmas, 34 Chemical sciences, 40 Engineering, 51 Physical sciences

Abstract:

© 2019 American Physical Society. Reducing the size of a superconductor below its characteristic length scales can either enhance or suppress its critical temperature (Tc). Depending on the bulk value of the electron-phonon coupling strength, electronic and phonon confinement effects will play different roles in the modification of Tc. Experimentally disentangling each contribution has remained a challenge. We have measured both the phonon density of states and Tc of Sn nanowires with diameters of 18, 35, and 100 nm in order to quantify the effects of phonon confinement on superconductivity. We observe a shift of the phonon frequency towards the low-energy region and an increase in the electron-phonon coupling constant that can account for the measured increase in Tc.