Does "have yet to" imply expectations?

I just wrote an email saying

I have written to you several times recently with various corrections but have yet to receive a response.

I'm wondering now whether this differs in normative content from "... but have not received a response yet". I feel that it does; it seems to carry more of an implication that it's not OK and I would have expected to receive a response by now – in fact I think that's precisely why I wrote it that way.

But in other contexts, there seems to be no such implication of expectations. For instance, in

The theory predicts additional particles, but evidence of their existence has yet to be found,

it doesn't seem to make much difference if we instead say "... but no evidence of their existence has been found yet". I don't feel that the first version expresses more of an expectation that evidence should have been found by now than the second version – if anything, it sounds a bit more like the evidence is bound to be found at some point than the second version does.

Can anyone throw some more light on this?

The expression is to have yet to do something. It is

used for saying that something has not happened or been done up to the present time, especially when you think it should have happened or been done (Macmillan)

So yes, it does express disappointment. But context will determine the degree of disappointment or if it is used more neutrally. Consider:

• The Scottish Office has yet to make a formal announcement. (It's overdue, they are delaying it too much, this sounds like a complaint)
• The film, starring Robert Carlyle, has yet to open in the Far East. (sounds more neutral, expressing expectation that it will happen in the future)

You have definitely used well this expression in your sentence. It is definitely a stronger complaint than if you said:

I have written to you several times recently with various corrections but have not yet received a response.

This sentence would rather express puzzlement because of the delay, whereas "have yet to receive a response" is more "stinging" and more likely to trigger an apology and action to solve the problem.

EDIT: Englishforuni gives similar examples indicating their negative connotation. It says:

This is formal English. It is used in formal situations, and is much less common in casual spoken English.

• I have written to your company several times in regard to this matter and I have yet to receive a reply. [This sentence comes from a letter of complaint. I've written to you but you haven't written back yet!] - This is very similar to your sentence.
• I have yet to receive an adequate explanation for your conduct! [This sounds like a teacher (or a boss!) talking. You haven't told me why you did what you did (and you are in trouble!).]

In the context of an e-mail, according to this reference (English for University.com ) this a very formal academic phrase that means, strictly speaking, nothing more than "not yet".

• have yet to < verb > = have not yet < verb >

Therefore, the notion that an answer is expected is not part of the understanding of the phrase per se but must be supported by the context: "we haven't got any answer but possibly you see fit to make none" or "as our communication was a request for specifications, we are waiting for your answer so as to proceed".

There are then two types of situations in which the phrase can be used, as the definition in MacMillan's dictionary mentions implicitly through the use of "especially".

used for saying that something has not happened or been done up to the present time, especially when you think it should have happened or been done
♦ The Scottish Office has yet to make a formal announcement.
♦ The film, starring Robert Carlyle, has yet to open in the Far East.
♦ The group has yet to find a replacement for the director who left in September.

In all these three examples the expectation of the realization of the action is a fairly logical consequence.
In some cases, such as in science and in particular in mathematics, there is often inherent to the situation no context to support expectations as to the realization of the action.

It appeared to be true that the equation had no positive integer solutions for x, y, z when n > 2, but the fact had yet to be proved.

(ref.) We beg the question when we take for granted what has yet to be proved.

(ref.) Early years education remains controversial. It is expensive and its effectiveness has yet to be proved . Indeed there are some who believe that early schooling can be positively harmful to some […]

As a conclusion it can be said that in using this phrase, any communication of expectation is only effected through the context. In some cases, when the reader is faced with an unfamiliar context, he/she might not be able to decide whether any degree of expectation of the realization of the action is legitimate.