portrait portrait

The 15th International Conference on

Vibrations at Surfaces

June 22-26, 2015 ▪ Donostia-San Sebastián, Spain

Donostia Igeldotik

Program

OverviewMondayTuesdayWednesdayThursdayFriday

Wednesday June 24

09:00-10:40 We1: E-ph coupling in novel 2D materials (I)
10:40-11:20 Coffee break
11:20-13:00 We2: E-ph coupling in novel 2D materials (II)
13:00-15:30 Poster session B
Afternoon off - some suggested activities can be found here
19:30-20:30 Public lecture by Polanyi in Kutxa Sala Andia (city center)

We2: E-ph coupling in novel 2D materials (II)

Chair: J. Wells, Trondheim, Norway

11:20-11:50 I. Y. Sklyadneva, San Sebastián, Spain & Tomsk, Russia
Electron-phonon scattering at surfaces and in ultrathin superconducting films: the effect of spin-orbit coupling
11:50-12:20 M. Calandra, Paris, France
Universal increase in the superconducting critical temperature of two-dimensional semiconductors at low doping by the electron-electron interaction
12:20-12:40 R. Arafune, Tsukuba, Japan
Importance of momentum resolved electron-phonon coupling in analysis of inelastic tunneling and photoemission spectroscopy
12:40-13:00 I. Errea, San Sebastián, Spain
Calculation of strongly anharmonic phonons in transition metal dichalcogenides

Invited talk

Universal increase in the superconducting critical temperature of two-dimensional semiconductors at low doping by the electron-electron interaction

M. Calandra, P. Zoccante, and F. Mauri

CNRS and Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université P. et M. Curie, Paris, France

In two-dimensional multivalley semiconductors, at low doping, even a moderate electron-electron interaction enhances the response to any perturbation inducing a valley polarization. If the valley polarization is due to the electron-phonon coupling, the electron-electron interaction results in an enhancement of the superconducting critical temperature. By performing first-principles calculations beyond density functional theory, we prove that this effect accounts for the unconventional doping dependence of the superconducting transition temperature (Tc) and of the magnetic susceptibility measured in LixZrNCI. Finally, we discuss what are the conditions for a maximal Tc enhancement in weakly doped two-dimensional semiconductors.

Calandra-1.jpg Calandra-2.jpg

Figure 1: (left) Phonon displacement of the 59 meV mode at K in a √3 × √3 bilayer supercell. The effect of the distortion on the electronic structure is shown on the right.

[1] M. Calandra, P. Zoccante, and F. Mauri, Phys. Rev. Lett. 114, 077001 (2015)