e-ph coupling ML-MoS2 EPW 5.1

Goal

The goal is to obtain the epc matrix element g(q,K) (note k = K = high symmetry point)

references :

FIG1a

Two-dimensional Frohlich interaction in transition-metal dichalcogenide monolayers:

Theoretical modeling and first-principles calculations

Sohier,Calandra, Mauri

DOI:

10.1103/PhysRevB.94.085415

FIG1b

Phonon-limited mobility in n-type single-layer MoS2 from first principles

Kaasbjerg, Kristen; Thygesen, Kristian S.; Jacobsen, Karsten

DOI:

10.1103/PhysRevB.85.115317

Combining these two results (note that the plot on the left represents only the 10% of the Gamma-K path) the expected behavior is

User-uploaded image: g_expected_behaviour.png

FIG 2

Result with EPW 5.1

Following http://epw.org.uk/School2018/School2018?action=downloadman&upname=Wed.4.Verdi.pdf

(all the input files and notes are reported below)

ibnd	jbnd	imode
7	7	7
8	8	8
7	7	8
8	8	7

FIG 3

among them the one that seems to approach (at least for half of the points) the desired results is 887

ibnd	jbnd	imode
8	8	7

FIG 4

Result with Quantum ESPRESSO

following http://epw.org.uk/School2018/School2018?action=downloadman&upname=Tue.5.Ponce.pdf

relatively good agreement with the expected result

Quantum espresso version : the one of the EPW school 2018

Input files and notes reported below

FIG 5

Check with EPW

FIG 6

User-uploaded image: epw_qe_comparison.png

FIG 7

Questions

error internal error, cannot bracket Ef

so I set Ef manually in the middle of the gap ~ -0.84 eV

from nscf.out “highest occupied, lowest unoccupied level (ev): -1.6587 0.0596”

Is this approach correct?

Why despite my filqf ='path.dat' (see below) is composed by 251 points, in the output I get

​​Goal

​​Result with EPW 5.1

​​Result with Quantum ESPRESSO

​​Check with EPW

​​

​​Questions

Goal

Result with EPW 5.1

Result with Quantum ESPRESSO

Check with EPW

Questions