Physics 223B: Homework 2
due January 31, 10am in Prof. Balents mailbox at the KITP
1. Hunds rules: In this problem, please apply the Hunds rule analysis given in class.
(a) Find the expected magnetic state (i.e. S, L, J quantum numbers) for Cr2+ , Cr3+ ,
Physics 223B: Homework 1
due January 24, 10am in Prof. Balents mailbox at the KITP
1. Layers: Suppose n twodimensional topological insulators are stacked atop one another.
Assuming electrons can tunnel between adjacent layers, and disorder is present, fo
Physics 223B: Homework 1  solutions
1. Layers: Suppose n twodimensional topological insulators are stacked atop one another.
Assuming electrons can tunnel between adjacent layers, and disorder is present, for which
n can you guarantee the existence of a
Physics 223B: Homework 2
due January 31, 10am in Prof. Balents mailbox at the KITP
1. Hunds rules: In this problem, please apply the Hunds rule analysis given in class.
(a) Find the expected magnetic state (i.e. S, L, J quantum numbers) for Cr2+ , Cr3+ ,
Physics 223b: Problem Set 3
due 10am, February 11, 2014 in Prof. Balents mailbox at the KITP
1. EuO: Europium oxide is a black, ferromagnetic insulator with the rock salt structure,
i.e. with Eu and O occupying the two interpenetrating fcc sublattices of
Physics 223b: Problem Set 3
due 10am, February 11, 2014 in Prof. Balents mailbox at the KITP
1. EuO: Europium oxide is a black, ferromagnetic insulator with the rock salt structure,
i.e. with Eu and O occupying the two interpenetrating fcc sublattices of
Physics 223b: Problem Set 5
due March 12, 2014 in class, or by email the same day.
1. Field and energy of vortices: Let us consider the GinzburgLandau free energy, in the
limit in which we assume (x) = n ei with constant n = ns /2:
s
s
h
2 ns
2e

 A2
Physics 223b: Problem Set 5
due March 12, 2014 in class, or by email the same day.
1. Field and energy of vortices: Let us consider the GinzburgLandau free energy, in the
limit in which we assume (x) = n ei with constant n = ns /2:
s
s
F =
d3 x
h
2 ns
2
Physics 223b: Problem Set 4
due 10am, February 21, 2014 in Prof. Balents mailbox at the KITP
1. Friedel Oscillations: Consider a free electron gas (Sommerfeld model) conned in one
direction by hard walls (innite potential barriers) to 0 < x < L, and innit
Physics 223b: Final Exam
You may consult the class notes, Solyom, and previous homeworks and solutions.
Do not discuss the exam problems with anyone except me!
due March 14, 2014 by 4pm, to my oce in KITP
1. IQHE versus TI: Consider three Hall bars: one m
Physics 223b: Problem Set 4
due 10am, February 21, 2014 in Prof. Balents mailbox at the KITP
Yes, just one problem, since this is somewhat last notice!
1. Friedel Oscillations: Consider a free electron gas (Sommerfeld model) conned in one
direction by har